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NYSIPM

Tree and Shrub Pest Mangement

10. Tree and Shrub Pest Management

Contents

Growing Degree Days

Key Plants and Key Pests

Sample IPM Program: for Gypsy Moth

Growing Degree Days

As we learn more about the biology of insect pests, we will be able to make timely management decisions. More accurate timing will allow us to reduce the number of pesticide applications needed. A system using growing degree days (GDD), which are more accurate than calendar dates, is used to determine when to apply pesticides to ornamental trees and shrubs. The climatological calendar begins on March 1, and the base temperature is 50° F. The GDDs are additive, giving a cumulative total for each day of the growing season.

These formulas, in degrees Fahrenheit, are used to determine GDD for each day:

(Maximum + minimum daily temperature) divided by 2 = Mean Temperature

Mean temperature (in Fahrenheit) minus 50 = Growing Degree Days (GDD)

**Note that the GDD can never be negative; if the above calculation yields a negative number, the number of GDDs for that day is zero.

Insect development can be tied directly to GDD accumulations, especially in the spring, when most activity begins. Apply the pesticide when GDDs have reached the levels listed in the tables. Consult your county Cooperative Extension educator for local GDD data for pest management. Known GDD information is included in Table 11.

Key Plants and Key Pests

Knowing which pests are most common and cause the most damage can also be helpful. Arborists and landscape contractors who manage pest problems are faced with over 175 insect pests and 110 different diseases, but not every pest occurs every year in damaging numbers. One goal in an integrated pest management approach is to monitor the major pests of the most common and significant plants in each landscape.

Table 10, which lists key plants and key pests, may help in planning your annual inspection schedule. The pests are grouped according to the first months in which they should be managed or controlled. Certain pests, such as aphids and mites, may continue to be pests for many months.

Sample IPM Program: for Gypsy Moth

The gypsy moth, a forest and shade tree pest that can cause widespread defoliation, is an introduced insect that has few natural enemies in our country. Management options for homeowners include planting resistant species; improving plant health by watering and fertilizing properly; removing and destroying egg masses anytime from September through mid-April; assessing the population and potential damage when young larvae are present in late May or early June and treating if needed; using bands around trees to trap larger larvae or to prevent larvae from entering the canopy; and destroying pupae as found.

Gypsy moth traps are available, but they aren’t recommended as a control measure. They are very useful in monitoring the spread of gypsy moth into new areas, but they trap only male moths, which does not significantly reduce the overall population.

Table 10. Key tree and shrub pests: Management by month
Ideal time to manage	Pest	Principal hosts
March (Dormant)	spider mite	evergreens, crabapple
	elongate hemlock scale	hemlock
	maple gall mite	maple
	pine bark adelgid	white pine
	eastern spruce gall adelgid	white and Norway spruces
	tuliptree scale	Tuliptree, star magnolia
	euonymous scale	pachysandra, euonymus
	black knot	plum, flowering cherry
Early April	white pine weevil	white pine (main shoot), spruce, Douglas fir
Mid- to late April	tent caterpillar	cherry, crabapple
	European pine sawfly	Mugo, scots, other pines
	anthracnose	maple, ash, oak, linden, dogwood
	hawthorn leaf spot	hawthorn
	honeylocust plant bug	honeylocust
	scab	apple, crabapple, hawthorn
	juniper twig blight	juniper, cedar
	Diplodia blight	pines (especially Austrian)
Early May	birch leafminer	birch
	aphid	deciduous plants
	dogwood borer	flowering dogwood
	euonymous scale	euonymus, pachysandra
	Cooley spruce gall adelgid	blue spruce
	white pine aphid	white pine
	cankerworm	oak, linden, beech, elm
	pachysandra blight	pachysandra
	viburnum leaf beetle	viburnum (esp. cranberry and arrowwood)
Mid- to late May	gypsy moth	oaks, maple, many trees
	spruce spider mite	spruce, juniper, arborvitae
	rhododendron borer	rhododendron
	lacebug	sycamore, walnut
	woolly beech aphid	beech
	black vine weevil	rhododendron, azalea, yew
	Verticillium wilt	maple
	black spot, mildew	rose
Early June	lace bugs	andromeda
	bronze birch borer	birch
	elongate hemlock scale	hemlock
	rose chafer	rose
	spruce canker (Cytospora)	spruce, fir
	Phytophthora wilt	rhododendron and azalea
Mid- to late June	bagworm	arborvitae, juniper
	leafhopper	maples, deciduous plants
	juniper scale	juniper
	white prunicola scale	flowering cherry and plum
July	Japanese beetle	many deciduous plants
	fall webworm	many deciduous plants
	spider mite	evergreen and deciduous plants

Table 11 Notes:

* Disease Sanitation Practices: Avoid crowding plants; allow air to circulate around and within plants. Prune to thin plants or plantings and/or to remove diseased parts. Prune only when conditions are dry, and, where feasible, disinfect pruning tools between cuts or between plants. Discard all diseased tissue and in autumn, rake and discard or destroy all fallen leaves, fruit, and branches. Avoid wetting foliage overnight or for long periods of time.

** Imidacloprid: Products containing imidacloprid are not registered for use in certain New York City and Long Island counties (Kings, Queens, Nassau, and Suffolk). Most formulations of imidacloprid once available to homeowners are now classified as restricted-use (for professional application only) in New York State. Check product status and label prior to purchase.

Table 11. Pest management for woody ornamentals (trees, shrubs, and vines) Also see Chapter 9 in Part I: Cultural Methods, of Pest Management Around the Home. For large trees, consult a professional applicator.
Plant	Pest	Some Pest Management Options
Andromeda (Pieris)	Lace bug (Stephanitis spp.)	Natural enemies are rarely abundant enough to control damaging populations. Infestations are more severe in sunny, exposed sites. If needed, treat in early to mid-May (120+ GDD). Spray undersurfaces of leaves. Use carbaryl, cyfluthrin, lambda-cyhalothrin, or insecticidal soap (potassium salts of fatty acids). Or use a systemic: disulfoton, or imidacloprid** (see note).
	Spider mites	When problem appears, use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides. Repeat application may be necessary. Or use disulfoton, as a systemic insecticide.
Arborvitae (Thuja)	Twig/Tip blight (Phomposis, Kabatina, Sirococcus, etc.)	Follow disease sanitation practices* (see note). Apply azoxystrobin (not near apples), or copper sulfate, following label directions.
	Arborvitae leafminers	Remove and destroy infested leaves from fall until early spring. If needed, treat with acephate, lambda-cyhalothrin, or spinosad. For larvae, apply in mid-May (150–260 GDD) and early August (1800–2200 GDD). For the moth stage, treat in mid-June (533–700 GDD). Or use imidacloprid** (see note) as a systemic.
	Arborvitae weevil	Apply neem oil.
	Bagworm	Handpick and remove. If needed, use Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, cyfluthrin, lambda-cyhalothrin, malathion, or spinosad. Spray in early to mid-June (600–900 GDD).
	Scales	To control crawlers, use acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil. Imidacloprid** (see note) can be used as a systemic.
	Spider mites	Use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Apply after new growth begins mid- to late May (192–363 GDD), and in late August through mid-September (2375–2806 GDD). Treat undersides of leaves as well as upper sides.
Azalea (Also see *Rhododendron*)	Flower blight (Ovulinia azaleae)	Follow disease sanitation practices* (see note). Apply chlorothalonil, myclobutanil, potassium bicarbonate, or propiconazole.
Azalea (Also see *Rhododendron*)	Phytophthora root rot	Use chlorothalonil especially before replanting site with new plants.
	Phytophthora shoot blight	Follow disease sanitation practices* (see note). Apply chlorothalonil, or copper ammonium carbonate.
	Azalea bark scale	Signs and symptoms include scales on bark, honeydew, sooty mold, leaf yellowing, and dieback. As a dormant spray in April, horticultural oil may be applied. To control crawlers (the mobile stage of scale insects), in late June to late July, apply acephate, carbaryl, cyfluthrin, horticultural oil, insecticidal soap, lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid** (see note) as a systemic.
Black vine weevil larva (above) and pupa (below)	Black vine weevil	For adult weevils, remove by hand, use pitfall traps, or burlap collars. If needed, treat with acephate or lambda-cyhalothrin in early June and early to mid-July. Apply full coverage spray to foliage and the soil beneath plants. To control the larvae, use entomophagous nematodes, or imidacloprid** (see note).
	Lace bug (Stephanitis spp.)	Infestations are more severe in sunny, exposed sites. If needed, use acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Spray the undersides of leaves. Or use a systemic: disulfoton, or imidacloprid** (see note).
	Sawfly	Apply acephate, carbaryl, imidacloprid**, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or spinosad. Check the pesticide label for proper growth stage for treatment. Some products are labeled only for larvae control.
	Southern red mite	In mid-June (618–802 GDD), use insecticidal soap (potassium salts of fatty acids) or lambda-cyhalothrin.
	Spider mites	If needed, use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Treat both upper and undersides of leaves. Or use disulfoton, as a systemic.
	Whitefly	Large populations may require the use of insecticides. Treat in early June (448–700 GDD), mid-July, and mid-August (1250–1500 GDD). Apply to undersides of leaves. Use acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use a systemic applied to the soil in early spring: disulfoton, or imidacloprid**.
Birch (Betula)	Aphids	If a problem, spray with acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, permethrin, or Mite-X (plant extracts). Or use imidacloprid** as a systemic.
	Birch leafminer	The larvae make blotch mines on the leaves. If a problem, apply two sprays: mid-May (190–290 GDD) and mid-June (530–700 GDD). Apply acephate, carbaryl, lambda-cyhalothrin, or permethrin. Or use imidacloprid** (see note) as a systemic.
	Birch skeletonizer	Spray when insect is observed, beginning about the second week of July (1266–1580 GDD). Use spinosad.
	Bronze birch borer	Borer damage causes dieback from the top of the tree downwards. Have trees treated by a certified applicator, or apply permethrin (check that label lists bronze birch borer) or imidacloprid**.
Boxelder (Acer negundo)	Boxelder bug	These plant bugs feed on developing seeds of boxelder and other maples (Acer species). One option is to remove seed-bearing trees. Or, when nymphs or adults are observed on the trees, apply carbaryl, cyfluthrin, or lambda-cyhalothrin.
Boxwood (Buxus)	Boxwood leafminer	Remove infested leaves by hand. If needed, treat during early June (448–700 GDD), getting good coverage of the undersides of leaves. Apply acephate, carbaryl, or malathion. Or use imidacloprid** as a systemic.
	Boxwood psyllid	To remove overwintering eggs, every few years prune tips of plants in winter or early spring before eggs hatch and destroy prunings. If needed, spray in late May before leaves become cupped (290–440 GDD). Apply carbaryl, horticultural oil, or insecticidal soap (potassium salts of fatty acids). Or use imidacloprid** as a systemic.
	Boxwood mite	Bronze stippling on foliage is a sign of mite feeding damage. Treat in early May (245–600 GDD), including undersides of leaves as well as upper sides. Use insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or Mite-X (plant extracts).
Clematis	Leaf spot and stem rot (Ascochyta clematidina)	Follow disease sanitation practices* (see note). Apply potassium bicarbonate following product label directions.
	Blister beetle	Handpick (wearing gloves) and destroy beetles. If needed, apply imidacloprid** or neem oil.
Cotoneaster	Fire blight	Prune out infected parts when plants are dry, making each cut several inches below areas of visible discoloration. Disinfect tools between cuts. If needed, apply Bacillus subtilis (for suppression).
	Lace bug	Treat twice: mid-May (293–363 GDD) and mid-July (1266–1544 GDD). Spray undersides of leaves. Use acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use a systemic: disulfoton, or imidacloprid** (see note).
	Pearleaf blister mite	Dark blister-like blotches on leaves are a symptom of these mites. Spray carbaryl as leaves emerge in spring. Treat undersides of leaves as well as upper sides.
	Pearslug (sawfly larva)	If needed, apply acephate, carbaryl, imidacloprid**, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or spinosad.
	Scales	Use acephate, cyfluthrin, horticultural oil, imidacloprid**, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil.
Crabapple (Malus)	Cedar-apple/hawthorn rust	Remove any nearby junipers, if feasible or when sphere-shaped galls on nearby junipers produce orange masses (jellylike and sometimes stringy), treat crabapple trees with chlorothalonil, myclobutanil, potassium bicarbonate, propiconazole, or sulfur.
	Powdery mildew	Follow disease sanitation practices* (see note). Apply Bacillus subtilis, chitosan, myclobutanil, potassium bicarbonate, propiconazole, or sulfur.
	Scab	Follow disease sanitation practices* (see note). Apply Bacillus subtilis (for suppression), chlorothalonil, myclobutanil, potassium bicarbonate, propiconazole, or sulfur.
	Aphids	Spray when observed, with cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Or use imidacloprid as a systemic. (DO NOT USE** imidacloprid if you plan to use fruit for cooking or eating).
	Eastern tent caterpillar	The larvae make webs in branch crotches and chew the leaves. Remove by hand. Remove and destroy egg masses over winter. If needed, treat once in late April to early May (90–190 GDD), with Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or spinosad.
	Gypsy Moth	Remove and destroy egg masses over winter. If needed, spray foliage in May after larvae hatch (90–448 GDD). Use Bacillus thuringiensis ssp. kurstaki, lambda-cyhalothrin, or cyfluthrin, before larvae reach 1 inch in length. Or use carbaryl, or spinosad.
	Japanese beetle	Handpick and remove beetles. Treat foliage when adults are observed and if needed, continue at weekly intervals until beetle season is over. Apply carbaryl, cyfluthrin, imidacloprid (DO NOT USE** imidacloprid if you plan to use fruit for cooking or eating), lambda-cyhalothrin, malathion, neem oil, pyrethrins plus PPB, or spinosad.
	Leaftiers and rollers	Handpick and destroy, where possible. Begin treating by June 1st, with carbaryl, cyfluthrin, lambda-cyhalothrin, neem oil, or spinosad.
	Roundheaded appletree borer	The adult beetles make exit holes in the bark near the tree base, after tunneling in the trunk as larvae. To prevent adults from laying eggs, ring the bottom 12–24 inches of the trunk with oviposition barriers in May. Use wire mosquito netting, hardware cloth, or several layers of newspapers. Barriers should be loose except at the bottom (cover with soil) and top (tie with cord). Remove barriers at the end of the season (October). Remove adults by hand, if seen. Imidacloprid may be used as a systemic (DO NOT USE** imidacloprid if you plan to use fruit for cooking or eating).
	Scales	If scale infestations are small, prune out affected plant parts. Horticultural oil may be applied at the dormant stage in April before new growth begins. For summer treatment when crawlers are active, use cyfluthrin, horticultural oil (summer or all-season type), insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid as a systemic (do not use** if you plan to use fruit for cooking or eating).
Dogwood (Cornus)	Anthracnose (Discula destructiva)	Follow disease sanitation practices* (see note). Apply chlorothalonil, copper ammonium carbonate, myclobutanil, potassium bicarbonate, propiconazole, or sulfur.
	Powdery mildew	Follow disease sanitation practices* (see note). Apply azoxystrobin (not near apples), Bacillus subtilis, copper ammonium carbonate, myclobutanil, or potassium bicarbonate.
	Cottony maple scale, Cottony maple leaf scale	If scale infestations are small, prune out affected plant parts. Horticultural oil may be applied at the dormant stage, in April before new growth begins. For crawlers in June (802–1265 GDD), spray with cyfluthrin, horticultural oil (summer or all-season type), insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid as a systemic (DO NOT USE** imidacloprid if you plan to use fruit for cooking or eating).
	Dogwood borer	Prune to maintain vigor. If necessary, imidacloprid may be used as a systemic (do not use** if you plan to use fruit for cooking or eating).
	European fruit lecanium scale	If scale infestations are small, prune out affected plant parts. There are many effective parasitic insects that help control the scale. If needed, use horticultural oil in mid-April to early May (35–145 GDD) for dormant treatment. In mid- to late July (1266–1645 GDD), treat for crawlers using cyfluthrin, a summer or all-season type horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid as a systemic. (DO NOT USE** imidacloprid if you plan to use fruit for cooking or eating).
Douglas-fir (Pseudotsuga)	Rhabdocline needlecast, and Swiss needlecast	Apply chlorothalonil, following label directions
	Cooley spruce gall adelgid	Do not plant Douglas-fir near blue spruce as the adelgid uses both as hosts. Damage is rarely serious. If needed, treat in early May (120–190 GDD) and again in early August (1500–1775 GDD). Use carbaryl, horticultural oil, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use imidacloprid** as a systemic.
	White pine weevil	Cut out and destroy wilted or dead leaders by the end of June. No pesticides are currently registered for homeowner use in New York State.
Dutchman’s pipe (Aristolochia)	Mealybug	Spray biweekly, mid-May through mid-June, with cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or malathion. Or use imidacloprid** (see note) as a systemic.
	Scales	Use cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil. Or use imidacloprid** as a systemic.
Elm (Ulmus)	Elm leaf beetle	Natural enemies are generally not abundant enough to provide control. In late May or early June (363-530 GDD), treat with cyfluthrin, lambda-cyhalothrin, permethrin, or spinosad. Or use imidacloprid** as a systemic.
Euonymus	Crown gall	Inspect new transplants carefully before adding to the landscape; no pesticides are currently available for home use.
	Euonymus caterpillar	Remove by hand (wear gloves). If needed, use spinosad.
	Euonymus scale	Symptoms of this scale include yellow spots on leaves and gray-white scurfy material on stems. Where possible, prune out scale-infested branches. Resistant euonymus species are recommended for future plantings. Horticultural oil may be applied as a dormant spray, in mid-April to early May (35–120 GDD). To control crawlers, treat in early to mid-June (533–820 GDD) and again in mid-July (1150–1388 GDD). Use a summer or all-season type horticultural oil, acephate, cyfluthrin, lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid** (see note) as a systemic.
Firethorn (Pyracantha)	Fire blight	Prune out infected parts when plants are dry, making each cut several inches below areas of visible discoloration. Disinfect tools between cuts. Apply Bacillus subtilis (for suppression).
	Scab (Venturia pyracantha)	Follow disease sanitation practices* (see note). If the disease has been severe, apply Bacillus subtilis (for suppression), chlorothalonil, or potassium bicarbonate.
	Lace bug	Treat twice, in mid-May (239–363 GDD) and in mid-July (1266–1544 GDD). Spray undersides of leaves, using acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use imidacloprid** (see note) as a systemic.
	Scale	During the dormant stage, use horticultural oil. Treat crawlers in summer with acephate, cyfluthrin, horticultural oil (all-season or summer type), insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid** as a systemic.
Flowering peach, cherry, and plum (Prunus) For trees used for edible fruits, see Chapter 11: Tree Fruit Pest Management. Do not use a systemic insecticide such as acephate or imidacloprid, if fruits will be used for cooking or eating.	Black knot	No pesticides are currently available. Follow disease sanitation practices* (see note) In winter, prune old knotted twigs and bury or burn. Destroy wild trees with knots along nearby hedgerows.
	Cherry leaf spot	Follow disease sanitation practices* (see note) In autumn, remove and destroy fallen leaves, fruits, and dead twigs. Apply copper sulfate or propiconazole, if needed.
	Monilinia shoot blight	Follow disease sanitation practices*. When blossoms open and again 10 days later, apply chlorothalonil or potassium bicarbonate.
	Aphids	Spray when observed, using acephate, cyfluthrin, (may not be effective for green peach aphid), horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Or use imidacloprid** as a systemic.
	Borers	The adult beetles make exit holes in the bark near the tree base, after tunneling in the trunk as larvae. To prevent adults from laying eggs, ring the bottom 12–24 inches of the trunk with oviposition barriers in May. Use wire mosquito netting, hardware cloth, or several layers of newspapers. Barriers should be loose except at the bottom (cover with soil) and top (tie with cord). Remove barriers at the end of the season (October). Permethrin may be used if the product label lists borers on that kind of tree. Or use imidacloprid** as a systemic.
	Eastern tent caterpillar	The larvae make webs in branch crotches, and chew the leaves. Remove by hand. Remove and destroy egg masses in winter. If needed, treat once in late April to early May (90–190 GDD), with acephate, Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, permethrin, or spinosad.
	European fruit lecanium scale	As a dormant spray in mid- to late April (35–145 GDD), apply horticultural oil. In mid-July (1266–1645 GDD) treat for crawlers with acephate, cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Japanese beetle	Remove by hand, where possible. Spray when observed and continue at weekly intervals, if needed. Use acephate, carbaryl, cyfluthrin, lambda-cyhalothrin, malathion, neem oil, pyrethrins plus PPB, or spinosad. Or use imidacloprid** as a systemic.
	Spider mites	Horticultural oil may be applied in April (7–121 GDD) before new growth begins. After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Treat undersides of leaves as well as upper sides.
	White prunicola scale	Signs and symptoms include a white coating on trunk and twigs, and dieback. Prune out where possible. Rather than applying pesticides, commercial applicators may powerwash the trunk to remove scales. Horticultural oil may be used as a dormant spray in April (35–145 GDD). Treat for crawlers in mid-June to early July (707–1151 GDD), using acephate, cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil. Or use imidacloprid** as a systemic.
Hawthorn (Crataegus)	Cedar-apple/cedar-hawthorn rust	Remove any nearby junipers, if feasible. When sphere-shaped galls on nearby junipers produce orange masses (jellylike and sometimes stringy), treat hawthorn with chlorothalonil, copper ammonium carbonate, myclobutanil, potassium bicarbonate, or propiconazole.
	Diplocarpon (Entomosporium, Fabreae) leaf spot	Follow disease sanitation practices* (see note). Plant only native hawthorns. Apply chlorothalonil or copper sulfate if needed.
	Fire blight	Prune out infected parts when plants are dry, making each cut several inches below areas of visible discoloration. Disinfect tools between cuts. Apply Bacillus subtilis (for suppression).
	Roundheaded appletree borer	The adult beetles make exit holes in the bark near the tree base, after tunneling in the trunk as larvae. To prevent adults from laying eggs, ring the bottom 12–24 inches of the trunk with oviposition barriers in May. Use wire mosquito netting, hardware cloth, or several layers of newspapers. Barriers should be loose except at the bottom (cover with soil) and top (tie with cord). Remove barriers at the end of the season (October). Imidacloprid** may be used as a systemic.
	Lace bug	Treat foliage, especially undersides of leaves, in mid-May (239–363 GDD) and again in mid-July (1266–1544 GDD). Use acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use imidacloprid** as a systemic.
	Leafminer	Spray twice, the first and third week of June, with acephate or lambda-cyhalothrin. Or use imidacloprid** as a systemic.
	Scales	Treat for scale crawlers with acephate, cyfluthrin, horticultural oil, imidacloprid**, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil.
	Spider mites	Horticultural oil may be applied at the dormant stage, in April (7–121 GDD) before new growth begins. After new growth begins mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Treat undersides of leaves as well as upper sides.
Hemlock (Tsuga)	Elongate hemlock (Fiorinia) scale	Avoid nitrogen fertilization. Scale symptoms include yellow needles and premature needle drop (note that some drop each year is normal, of needles that are a few years old). Horticultural oil may be applied as a dormant spray in early April (7-120 GDD). In early June (360–700 GDD), treat for crawlers with acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Hemlock rust mite (eriophyid mite)	In early April (7–22 GDD), apply a horticultural oil labeled for mites.
	Hemlock scale	Avoid nitrogen fertilization. Scale symptoms include yellow needles and premature needle drop. Parasites often keep this scale under control. Horticultural oil may be applied as a dormant spray in April (35–121 GDD). In mid-July to mid-August (1388–2154 GDD) treat for crawlers with acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Hemlock woolly adelgid	Signs and symptoms include cottony white egg sacs along branches, needle yellowing, and dieback. Western hemlocks appear to be resistant. Do not apply nitrogen fertilizer to infested hemlocks, as it promotes adelgid growth. At the dormant stage (late April to early May), apply horticultural oil. In late June or late September and the following year in early June, treat with insecticidal soap. Thorough coverage with oil or soap is necessary. Hire certified applicators who have proper equipment if trees are tall or many trees are to be treated. Imidacloprid** (see note) may be used as a systemic.
	Spider mites	After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), apply acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Treat undersides of leaves as well as upper sides.
Holly (Ilex)	Cottony maple leaf scale	Use horticultural oil for a dormant spray in April. For crawlers, spray in June (802–1265 GDD) with acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Native holly leafminer	Remove and destroy mined leaves before May. If needed, spray in mid-May (198–298 GDD) and again in early July (1029-1266 GDD), using acephate, carbaryl, or lambda-cyhalothrin. Or use disulfoton or imidacloprid**, as a systemic.
	Scales	Treat for crawlers with acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Spider mites	After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides. Or use disulfoton, as a systemic.
	Twobanded Japanese weevil	Handpick and remove, if possible. Spray in late July or in August (1644–2271 GDD), with neem oil.
	Whitefly	Apply acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use a systemic: disulfoton, or imidacloprid** (see note).
Honeylocust (Gleditsia)	Honeylocust plant bug	Spray from late April through early May (58–246 GDD), with carbaryl or lambda-cyhalothrin.
	Pod gall midge	Spray in mid-May (199–229 GDD) with carbaryl.
	Scales	Treat for scale crawlers with acephate, cyfluthrin, horticultural oil, imidacloprid**, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil.
	Spider mites	After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), apply acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides.
Honeysuckle (Lonicera)	Honeysuckle aphid	Causes witches’-brooming. Resistant cultivars are available. If needed, spray as leaves begin spring expansion, 2 weeks later, and again 4 weeks after that, using acephate, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Or use a systemic: disulfoton, or imidacloprid** (see note).
	Leafroller	At first sign of insects, apply cyfluthrin, lambda-cyhalothrin, neem oil, or spinosad.
	Spider mites	After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), apply acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides. Or use disulfoton, as a systemic insecticide.
	Whitefly	Large populations may require the use of insecticides. Treat undersides of leaves in early June (448–700 GDD), mid-July, and mid-August (1250–1500 GDD). Use acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use a systemic: disulfoton, or imidacloprid** (see note).
Horsechestnut and Buckeye (Aesculus)	Leaf blotch (Guignardia aesculi, Phyllosticta paviae)	Follow disease sanitation practices* (see note). On small trees, in spring when new leaves emerge, spray chlorothalonil three times at intervals of 10 to 14 days. For large trees, consult a professional applicator.
Hydrangea	Fungal leaf spot	Follow disease sanitation practices* (see note). If needed, apply Bacillus subtilis, chlorothalonil (see note), copper soap (copper octanoate), copper sulfate, myclobutanil, neem oil, or potassium bicarbonate. Note: chlorothalonil may discolor blossoms; apply to foliage only and test on a small area first.
	Powdery mildew	Follow disease sanitation practices* (see note). If needed, apply Bacillus subtilis, chitosan, copper soap (copper octanoate), myclobutanil, neem oil, potassium bicarbonate, or sulfur.
	Aphids	Apply if needed: acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Or use a systemic: disulfoton, or imidacloprid** (see note).
	Leaftier (caterpillar)	Remove by hand. If needed, spray as soon as noticed. Best results are when larvae are exposed, rather than hidden within tied leaves. Use carbaryl, cyfluthrin, horticultural oil, lambda-cyhalothrin, neem oil, or spinosad.
	Spider mites	Spray if needed, using acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Good coverage of leaf undersides is important for control. Repeat spraying may be necessary. Or use disulfoton, as a systemic.
Ivy (Boston) (Parthenocissus)	Fungal leaf spot (Guignardia, anthracnose)	Follow disease sanitation practices* (see note). Apply copper ammonium carbonate following label directions.
	Powdery mildew	Follow disease sanitation practices* (see note). Apply Bacillus subtilis, chitosan, or copper ammonium carbonate.
	Japanese beetle	Handpick and remove adults, where possible. If needed (usually in July), apply acephate, cyfluthrin, lambda-cyfluthrin, malathion, neem oil, or pyrethrins plus PPB. Or use imidacloprid** (see note) as a systemic.
	Scales	Spray at two-week intervals during June and July. Use acephate, cyfluthrin, horticultural oil, lambda-cyfluthrin, or neem oil. Or use imidacloprid** as a systemic.
	Spider mites	Spray in May and repeat only if needed. Use acephate, insecticidal soap (potassium salts of fatty acids), lambda-cyfluthrin, malathion, neem oil, or Mite-X (plant extracts).
Ivy (English) (Hedera)	Anthracnose (Colletotrichum)	Follow disease sanitation practices* (see note). Apply azoxystrobin (not near apples), Bacillus subtilis, copper ammonium carbonate, or potassium bicarbonate.
	Bacterial leaf spot (Xanthomonas hederae)	Follow disease sanitation practices* (see note). Apply Bacillus subtilis following label directions.
	Scales	Spray at two-week intervals during June and July, with acephate, cyfluthrin, horticultural oil, lambda-cyfluthrin, or neem oil. Or use imidacloprid** as a systemic.
	Spider mites	Spray in May and repeat only if needed. Use acephate, insecticidal soap (potassium salts of fatty acids), lambda-cyfluthrin, neem oil, or Mite-X (plant extracts).
Juniper (Juniperus)	Cedar-apple/cedar hawthorn rust	Remove galls in early spring. Beginning in early August, spray with copper ammonium carbonate or potassium bicarbonate.
	Tip blight (Phomopsis, Kabatina, etc.)		Follow disease sanitation practices* (see note). Confirm diagnosis and, if appropriate, spray at two week intervals throughout the growing season or according to label directions. Depending on the blight fungus species (check product labels prior to purchase), apply azoxystrobin (not near apples), potassium bicarbonate, or propiconazole.

	Arborvitae leafminers	Treat for larvae with acephate or lambda-cyfluthrin in mid-May (150–260 GDD) with a second application in early August (1800–2200 GDD). Or use imidacloprid** (see note) as a systemic.
	Juniper scale	Symptoms include yellowing foliage, turning brown in severe infestations. Prune out infested areas, where possible. Apply horticultural oil for dormant spray in mid- to late April (22–148 GDD). In mid- to late June and early July (707–1260 GDD), use acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Juniper webworm	Spray in late July through early August (1645–1917 GDD), using acephate, carbaryl, or spinosad.
	Spider mites	After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides.
Lilac (Syringa)	Powdery mildew	Follow disease sanitation practices* (see note). Apply Bacillus subtilis, chitosan, chlorothalonil, copper ammonium carbonate, or propiconazole.
	Bacterial blight	Follow disease sanitation practices* (see note). Apply Bacillus subtilis or copper ammonium carbonate.
	Lilac borer/ash borer	Prune out and destroy infested portions. Imidacloprid** (see note) may be used as a systemic.
	Lilac leafminer	Spray in mid- to late May (246–363 GDD) and again in mid- to late July (1388–1644 GDD) with acephate, lambda-cyhalothrin, or permethrin. Or use imidacloprid** as a systemic.
	Oystershell scale	If scale infestations are small, prune out affected plant parts. Horticultural oil may be applied as a dormant spray in April (7–91 GDD). Treat for crawlers in late May through mid-June (363–707 GDD), using acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, malathion, neem oil, or permethrin. Or use imidacloprid** (see note) as a systemic.
	Twobanded Japanese weevil	Spray in late July or in August (1644-2271 GDD) with neem oil. Imidacloprid** (see note) may be used to control the larvae.
	White prunicola scale	Signs and symptoms include a white coating on the trunk and twigs, and dieback. Prune out where possible. Rather than applying pesticides, commercial applicators may powerwash to remove scales. Horticultural oil may be used as a dormant spray in April (35–145 GDD). Treat for crawlers once in mid-June to early July (707–1151 GDD) using cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** as a systemic.
Linden (littleleaf) (Tilia)	Japanese beetle	Handpick and remove, where possible on small trees. If needed, use acephate, cyfluthrin, lambda-cyhalothrin, malathion, neem oil, or pyrethrins plus PPB. Or use imidacloprid** as a systemic.
London plane and Sycamore (Platanus)	Anthracnose	Follow disease sanitation practices* (see note). For small trees only, spray with chlorothalonil, copper ammonium carbonate, or copper soap (copper octanoate). For large trees consult a professional applicator.
Note: Check pesticide label for plant species.	Powdery mildew	Follow disease sanitation practices* (see note). If needed, spray with Bacillus subtilis, or copper ammonium carbonate.
	American plum borer	Imidacloprid** (see note) may be used as a systemic.
	Lace bug	Spray in mid-May (239–363 GDD) and again in mid-July (1266–1544 GDD) with acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use imidacloprid** as a systemic.
	Scales	Treat for scale crawlers using cyfluthrin, horticultural oil, imidacloprid**, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin.
Magnolia	Magnolia scale	If scale infestations are small, it may be possible to prune out affected twigs or scrub scales off branches. Horticultural oil may be used as a dormant spray in April (22–91 GDD). In early October, spray for crawlers on branches using cyfluthrin, horticultural oil, lambda-cyhalothrin, or malathion. Two fall applications 7–10 days apart may be needed. Or use imidacloprid** as a systemic.
Maple (Acer)	Anthracnose	Follow disease sanitation practices* (see note). For small trees only, apply azoxystrobin (not near apples) or copper ammonium carbonate. For large trees, consult a professional applicator.
	Tar spot (Rhytisma)	Follow disease sanitation practices* (see note). In most years, when tar spot develops later in the season, it does not cause major damage to the tree. Rake up and remove dead leaves in the fall, to reduce infection the following year. On Norway maple, especially in drought years, tar spot can become abundant enough to cause premature leaf drop. For large trees, consult a professional applicator.
	Aphids	Use acephate (may cause leaf injury on sugar or red maples), cyfluthrin, horticultural oil, insecticidal soap (but not on Japanese maples), lambda-cyhalothrin, malathion, or Mite-X (plant extracts). Or use imidacloprid** (see note) as a systemic.
	Boxelder bug	These feed on developing seeds of maples (Acer species), including boxelder and others. If numbers of nymphs or adults are seen, apply carbaryl, cyfluthrin, or lambda-cyhalothrin.
	Cottony maple scale, and Cottony maple leaf scale	If scale infestations are small, prune out affected plant parts. Horticultural oil may be applied as a dormant spray in mid- to late April. In late June and early July (801–1265 GDD), treat for crawlers using acephate (may cause leaf injury on sugar or red maples), carbaryl, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or malathion. Or use imidacloprid** (see note) as a systemic.
	Forest tent caterpillars	Parasites are often abundant enough to provide partial control. In mid- to late May (192–363 GDD), small trees may be treated with Bt (Bacillus thuringiensis ssp. kurstaki), acephate (may cause leaf injury on sugar or red maples), carbaryl, lambda-cyhalothrin, or malathion. For large trees, consult a professional applicator.
	Maple bladdergall (eriophyid) mites	The tiny leaf galls may be aesthetically displeasing, but are not seriously harmful to the tree. Horticultural oil labeled for mites may be used as a dormant spray in mid- to late April.
Mountain ash (Sorbus)	Fire blight	Prune out infected parts when plants are dry, making each cut several inches below areas of visible discoloration. Disinfect tools between cuts. Apply Bacillus subtilis (for suppression).
	Mountain ash sawfly	When larvae are observed, usually in early to mid-June (448–707 GDD), apply carbaryl, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or spinosad. Or use imidacloprid** (see note) as a systemic.
	Rose Chafer and Japanese Beetle	Handpick and remove, where possible. If needed, use carbaryl, cyfluthrin, lambda-cyhalothrin, malathion, or neem oil. NOTE: Check product label for which type of beetle is listed. Spray when observed and continue at weekly intervals until beetle season is over. Or use imidacloprid** (see note) as a systemic.
	Roundheaded appletree borer	The adult beetles make exit holes in the bark near the tree base, after tunneling in the trunk as larvae. To prevent adults from laying eggs, ring the bottom 12–24 inches of the trunk with oviposition barriers in May. Use wire mosquito netting, hardware cloth, or several layers of newspapers. Barriers should be loose except at the bottom (cover with soil) and top (tie with cord). Remove barriers at the end of the season (October). Imidacloprid** (see note) may be used as a systemic.
	Spider mites	Treat after new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD). Use horticultural oil (summer or all-season type), insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Treat undersides of leaves as well as upper sides.
Mountain laurel (Kalmia)	Fungal leaf spot	Follow disease sanitation practices* (see note). Apply Bacillus subtilis (for suppression) or chlorothalonil.
	Black vine weevil	For adult weevils, remove by hand, use pitfall traps, or burlap collars. Apply lambda-cyhalothrin if needed. To control larvae, imidacloprid** may be used as a systemic.
	Borer	To control larvae, imidacloprid** (see note) may be used as a systemic.
	Lace bug	Natural enemies are rarely abundant enough to affect damaging populations. Infestations are more severe in sunny, exposed sites. In early to mid-May (120+ GDD), spray undersurfaces of leaves with carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), or lambda-cyhalothrin. Or use a systemic: disulfoton, or imidacloprid**.
	Whitefly	Large populations may require the use of insecticides. In early June (448–700 GDD), mid-July, and mid-August (1250–1500 GDD), treat undersides of leaves with cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or malathion. Or use a systemic: disulfoton, or imidacloprid** (see note).
Oak (Quercus) Gypsy moth larva	Anthracnose and other leaf spot diseases	Follow disease sanitation practices* (see note). If disease has been severe, spray with azoxystrobin (not near apples), chlorothalonil (check label: some products should only be used on oaks in the red oak group, not white oaks), or copper ammonium carbonate. Or use sulfur or propiconazole, depending on the disease. Check labels to see which kinds of leafspots are listed.
	Blotch leafminers	Control is dependent on early treatment when mines are less than 1/4 inch long (533–912 GDD). Apply acephate, carbaryl, lambda-cyhalothrin, permethrin, or spinosad. Or use imidacloprid** (see note) as a systemic.
	Cankerworms	Treat when first observed in the spring. Use Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, cyfluthrin, lambda-cyhalothrin, permethrin, or spinosad.
	Gypsy moth	Remove and destroy egg masses over winter. If needed, spray foliage in May after larvae hatch (90–448 GDD). Use acephate, Bt (Bacillus thuringiensis ssp. kurstaki), carbaryl, cyfluthrin, lambda-cyhalothrin, or spinosad. If using Bt, apply before larvae reach 1 inch in length.
	Leaf galls and Oak galls	Although these may be aesthetically displeasing, galls on the leaves generally do not cause major damage to the tree. If desired, handpick and destroy galls, where practicable. Carbaryl may be used for the tiny gall wasps and gall midges, if necessary.
	Leaftiers	This pest is minor, and control is usually not necessary. Cyfluthrin, lambda-cyhalothrin, neem oil, or spinosad may be used.
	Scales	Treat for scale crawlers with acephate, cyfluthrin, horticultural oil, imidacloprid**, lambda-cyhalothrin, malathion, or neem oil.
	Skeletonizer	Spray foliage in early June (448–707 GDD) and if needed, again in early August (1798–2155 GDD). Use carbaryl, cyfluthrin, lambda-cyhalothrin, or spinosad.
Pachysandra	Volutella blight	Follow disease sanitation practices* (see note). When new leaf growth starts, spray with chlorothalonil following label directions.

	Euonymus scale	Signs and symptoms include yellow spots on leaves and gray-white scurfy material on stems. Where possible, prune out scale-infested branches. Horticultural oil may be used as a dormant spray in mid-April to early May (35–120 GDD). In early to mid-June (533–820 GDD); and again in mid-July (1150–1388 GDD), use horticultural oil, cyfluthrin, insecticidal soap (potassium salts of fatty acids), malathion, or neem oil. Or use imidacloprid** (see note) as a systemic.
Pieris	See Andromeda.
Pine (Pinus)	Diplodia tip blight (Sphaeropsis)	Follow disease sanitation practices* (see note). Apply potassium bicarbonate or propiconazole, if needed.
	Aphids	Apply horticultural oil as a dormant spray in mid- to late April. When aphids are seen during the growing season, acephate, cyfluthrin, lambda-cyhalothrin, neem oil, or Mite-X (plant extracts) may be applied. However, pesticides applied to foliage may kill predatory insects, which could otherwise help control insect pests. Or use imidacloprid** (see note) as a systemic.
	European pine shoot moth	Prune out and destroy dead buds and dying shoots. Spray in late April (34–121 GDD) with carbaryl, malathion, or permethrin.
	Gypsy moth	Remove egg masses over winter. Gypsy moth is usually not a serious problem on pine unless population levels are high. If necessary, spray in mid- to late May or when needed, using carbaryl, cyfluthrin, lambda-cyhalothrin, or spinosad.
	Nantucket pine tip moth	Spray in May (121–448 GDD) and again in late July through early August (1514–1917 GDD). Use acephate, lambda-cyhalothrin, or permethrin. Or use imidacloprid** (see note) as a systemic.
	Pine bark adelgid	Remove adelgids from the bark with a high pressure wash or scrub off with a brush. If needed, apply horticultural oil to the bark in April (22–58 GDD). Or use insecticidal soap (potassium salts of fatty acids), or imidacloprid** (see note).
	Pine false webworm	In early June, apply lambda-cyhalothrin or spinosad. Or use imidacloprid** (see note) as a systemic.
	Pine needle scale	Use horticultural oil for dormant treatment in mid-April. In late May (298–448 GDD) and late July (1290–1917 GDD), treat for crawlers using acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, malathion, or permethrin. Or use imidacloprid** as a systemic.
	Pine sawflies	Hand pick or prune off and destroy colonies. Or spot treat when observed, using acephate, carbaryl, lambda-cyhalothrin, or spinosad. Or use imidacloprid** (see note) as a systemic.
	Pine thrips (especially on Japanese black pine)	Treat once, in mid-April to Mid-May using malathion or permethrin (for thrips on exposed surfaces). Or use imidacloprid** as a systemic.
	Pine tortoise scale	Use horticultural oil for dormant treatment in mid- to late April (58–148 GDD). In mid- to late June (618–1050 GDD), treat for crawlers using acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or malathion. Or use imidacloprid** as a systemic.
	Spittlebug	Remove spittle masses and insects by hand. If needed, spray in early to mid-May (148–298 GDD) using acephate, carbaryl, or lambda-cyhalothrin.
	White pine aphid	Treat in April (7–121 GDD), again early to mid-May (121–246 GDD), and if needed, again in mid-August (1917–2271 GDD). Apply cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, permethrin, or Mite-X (plant extracts). Or use imidacloprid** as a systemic.
	White pine weevil	Cut out and destroy wilted or dead leaders by the end of June. No pesticides are registered for homeowner use.
	Zimmerman pine moth	Some products containing permethrin may be used; check labels.
Privet (Ligustrum)	Privet rust mite	Treat with carbaryl or Mite-X (plant extracts) in the last 10 days of May through mid-June (298–802 GDD) and in mid-July (1266–1515 GDD). Apply to both sides of foliage.
	Privet thrips	Treat once in mid-May to early-June (192–618 GDD) and once during first 10 days of July (1029–1266 GDD). Use carbaryl, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Or use a systemic: disulfoton, or imidacloprid** (see note).
	Scales	Prune out severely infested plant parts. Treat for crawlers using acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Twobanded Japanese weevil	Spray in late July or in August (1644–2271 GDD) with neem oil. Or use imidacloprid** as a systemic.
	White prunicola scale	Signs and symptoms include white coating on trunk and twigs, and dieback. Prune out where possible or wash off scales with high pressure power washing. Horticultural oil may be used as a dormant spray in April (35–145 GDD). Treat for crawlers one time in mid-June to early July (707–1151 GDD) using cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
Pyracantha	See Firethorn.
Quince (Chaenomeles)	Fire blight	Prune out infected parts when plants are dry, making each cut several inches below areas of visible discoloration. Disinfect tools between cuts. Apply Bacillus subtilis (for suppression) if needed.
	Rust	Follow disease sanitation practices* (see note). Apply chlorothalonil following label directions.
Rhododendron (Also see Azalea.)	Rhododendron gall midge	Open-grown plants and those with good air circulation are less susceptible to injury. Remove gall-deformed leaves by hand. Apply spinosad or carbaryl at foliage budbreak in mid- to late May (192–363 GDD).
Rose (Rosa)	Black spot	Follow disease sanitation practices* (see note). Many pesticides are available including: Bacillus subtilis, chlorothalonil, copper ammonium carbonate, copper soap (copper octanoate), copper sulfate, myclobutanil, neem oil, potassium bicarbonate, propiconazole, and sulfur. Use according to label directions.

	Botrytis blight (gray mold)	Follow disease sanitation practices* (see note). If blight symptoms develop during wet periods, apply azoxystrobin (not near apples), Bacillus subtilis, chlorothalonil, copper ammonium carbonate, copper soap (copper octanoate), myclobutanil, neem oil, or potassium bicarbonate.
	Crown gall	Inspect new transplants carefully before adding to the landscape. No pesticides are currently available for home use.
	Powdery mildew (Sphaerotheca)	Follow disease sanitation practices* (see note). When disease appears, apply azoxystrobin (not near apples), Bacillus subtilis, copper ammonium carbonate, copper soap (copper octanoate), copper sulfate, lime sulfur (calcium polysulfide), myclobutanil, neem oil, potassium bicarbonate, propiconazole, or sulfur.
	Rust (Phragmidium)	Follow disease sanitation practices* (see note). When rust pustules are first seen on lower leaf surfaces, apply azoxystrobin (not near apples), Bacillus subtilis, copper soap (copper octanoate), copper sulfate, lime sulfur (calcium polysulfide), myclobutanil, neem oil, potassium bicarbonate, propiconazole, or sulfur.
	Aphids	Spray when aphids first appear and follow label directions for additional applications if needed. Use acephate, carbaryl, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Or use a systemic: disulfoton, or imidacloprid** (see note).
	Japanese beetle	Handpick and remove. If necessary, spray when observed and continue at weekly intervals until beetle season is over. Use acephate, carbaryl, cyfluthrin, lambda-cyhalothrin, malathion, neem oil, permethrin, or spinosad. Or use imidacloprid** (see note) as a systemic.
	Leafhopper	Spray 3 times at four-week intervals, beginning in June. Use acephate, carbaryl, cyfluthrin, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or malathion. Or use a systemic: disulfoton, or imidacloprid**.
	Rose chafer	This beetle has few natural enemies. Handpick beetles and remove. If needed, spray in early June when beetles are present using carbaryl, neem oil, or permethrin.
	Rose midge	Use acephate or lambda-cyhalothrin following label directions.
	Roseslug and other sawfly larvae	Handpick where possible. If needed, spray with acephate, carbaryl, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or spinosad. Or use imidacloprid** (see note) as a systemic.
	Spider mites	If needed, use acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Treat undersides of leaves as well as upper sides. Or use disulfoton, as a systemic.
Spruce (Picea)	Rhizosphaera needle cast	This disease is most often found on trees weakened by other causes and is rarely severe enough to warrant control measures. If damage is not tolerable, spray with chlorothalonil. Make first application when new growth is 1/2 to 2 inches long and make additional applications at 3 to 4 week intervals while conditions favor disease.
	Cooley spruce gall adelgid	Apply horticultural oil as a dormant spray in mid- to late April (22–91 GDD) just before buds begin to break. In mid-September (1850–1950 GDD), apply carbaryl, horticultural oil, or insecticidal soap. Or use imidacloprid** (see note) as a systemic. Cooley spruce gall (pineapple shaped galls at tip of spruce shoot)
	Eastern spruce gall adelgid	This adelgid makes galls at the base of new shoots on Norway spruce. Spray in mid-April to early May (22–170 GDD) or treat in mid- to late September when insects emerge from galls and majority of galls are open. Use horticultural oil or insecticidal soap. Or use imidacloprid** as a systemic. Caution: Horticultural oils may discolor the foliage of Blue spruce.
	Sawfly	Hand pick or prune off and destroy colonies. If needed, spot treat when seen using acephate, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, or spinosad. Or use imidacloprid** as a systemic.
	Spider mites	Horticultural oil may be used as a dormant spray in April (7–121 GDD) before new growth begins. After new growth begins in mid- to late May (192–363 GDD) and in late August through mid-September (2375–2806 GDD), treat with acephate, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, neem oil, or Mite-X (plant extracts). Treat undersides of leaves as well as upper sides.
	Spruce bud scale	Horticultural oil may be used as a dormant spray in mid-April (22–121 GDD). Treat for crawlers in late June and early July using cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Spruce needle miner	Prune out clusters of needles held together by silk in early spring. In early to mid-June (448–802 GDD), if needed, apply carbaryl.
	White pine weevil	Cut out and destroy wilted or dead leaders by the end of June. No pesticides are registered for homeowner use.
Sycamore	See London plane.
Taxus (Yew)	Black vine weevil (Taxus weevil)	Handpick and remove adults when seen. Pitfall traps or beating sheets can help monitor adult activity. To control adults, use acephate or lambda-cyhalothrin in mid-June (about 10 days earlier for Long Island) and early to mid-July. Apply full coverage spray to foliage and the soil beneath plants. Or use imidacloprid** (see note) as a systemic. Entomophagous nematodes may be used for the soil-dwelling stage (larvae) during late summer to early fall.
	Fletcher scale	If scale infestations are small, prune out affected plant parts. Use horticultural oil as a dormant spray in April (35–148 GDD). Treat for crawlers in early July (1029–1388 GDD) and early September (2515–2800 GDD) using acephate, horticultural oil, lambda-cyhalothrin, or malathion. Or use imidacloprid** (see note) as a systemic.
	Mealybug	Use horticultural oil as a dormant spray in April (7–91 GDD). Spray again in mid-May through early June (246–618 GDD) using carbaryl, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or permethrin. Or use imidacloprid** (see note) as a systemic.
Viburnum	Downy mildew (Plasmopara)	Follow disease sanitation practices* (see note). Apply Bacillus subtilis (for suppression) in spring, following label directions.
	Aphids	Spray in May, and repeat only if needed. Use acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, neem oil, or permethrin. Or use a systemic: disulfoton, or imidacloprid** (see note).
	Cottony maple leaf scale	Use horticultural oil as a dormant spray in April. For crawlers, spray in June (802–1265 GDD) using acephate, cyfluthrin, horticultural oil, lambda-cyhalothrin, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Viburnum leaf beetle	This beetle is a recent invasive insect in the Northeast. Remove and destroy twigs with egg masses (usually on newest growth) between October and April. If needed, spray with cyfluthrin or pyrethrins plus PPB when larvae first appear in early May (75–100 GDD) or if damage from adults (mid- to late summer) is excessive. Or use imidacloprid** (see note) as a systemic.
Willow (Salix)	Aphids	Spray in late May, and repeat in mid- to early July if aphid populations are still present. Apply acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, Mite-X (plant extracts), or neem oil. Or use imidacloprid** as a systemic.
	Scales	Treat for crawlers using acephate, cyfluthrin, horticultural oil, insecticidal soap (potassium salts of fatty acids), lambda-cyhalothrin, malathion, or neem oil. Or use imidacloprid** (see note) as a systemic.
	Willow leaf beetle, Imported willow leaf beetle	In mid-May to early June (192–448 GDD) apply acephate, carbaryl, cyfluthrin, or neem oil. Or use imidacloprid** as a systemic.
Yew (Taxus)	See Taxus.

Pest Management Guidelines A Cornell Cooperative Extension Publication	New York Pest Management Guidelines
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