Pests of Specific Crops

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Pest Description CORYLUS - HAZELNUT Diseases: Bacterial Blight (Xanthomonas arboricola pv. corylina): New buds and shoots are blighted and oneand two-year-old twigs may have sunken purple-brown cankers. Trees may be girdled and killed at the base of the trunk (crown) during the first 10 years. Tissue under the bark of cankers and infected crowns is reddishbrown. Leaves may have small (2-3 mm), angular, water-soaked spots that turn reddishbrown. Roots are seldom infected. Eastern Filbert Blight (Anisogramma anomala): Infected branches show up from July to September when leaves turn brown but remain on the branch. Oblong, raised bumps (fungal fruiting bodies) in relatively straight rows begin to form under the bark of infected branches in June. By August the bumps are white, football shaped structures that have broken through the bark. These fungal structures turn black as they mature in the fall. COTONEASTER Diseases: Bacterial Blight (Pseudomonas syringae pv. syringae): New growth wilts and turns black in the spring. The disease may occur at any time in propagation houses. It is common at the Coast. Dark Berry (Phytophthora cactorum): Berries turn brown to black and eventually shrivel up. Fire Blight (Erwinia amylovora): Flowers and new shoots wilt suddenly and turn brown. Dead leaves hang downward on affected twigs. This disease is rare at the Coast but common in the Interior. Scab (Venturia sp.): This fungus causes shedding of blossoms, and dark, blotchy spots on leaves and fruit. Diseased leaves can be curled and distorted. New infections can occur whenever there is a moderate to prolonged rainy period Chemical Control (rate per 100 L water; or per unit area if indicated) COPPER SPRAY 50: 300-900 g depending on tree size. Apply before fall rains, at ¾ leaf fall and before spring bud break. Maximum 3 applications per year. BRAVO 500: 6.72 L/ha COPPER SPRAY 50: 300-900 g. Apply from bud swell to bud break at 10-14 day intervals; up to 3 applications per year. Use low rate on small trees and high rate for large trees. FLINT 50WG: 140-280g/ha QUADRIS: 90 mL. From bud swell to bud break (approximately mid-March to mid-May), apply at 7-10 day intervals prior to disease development. Cultural Management See the Ministry’s Hazelnut Pest Management Guide. Protect trees from sunscald during the first few years. The bacterium infects through wounds, so disinfect pruners between cuts. Prune out infected branches 60-90 cm below lesions. ‘Barcelona’ is highly susceptible; ‘Du Chilly’ is susceptible; ‘Daviana’ is intermediate and ‘Hall’s Giant’ is resistant. If you see suspicious symptoms, contact the Ministry’s Plant Pathologist in Abbotsford. The CFIA has initiated the process to deregulate the disease. ‘Daviana’, ‘Butler’ and ‘Ennis’ are highly susceptible; ‘Barcelona’ is moderately susceptible; and ‘Willamette’ and ‘Hall’s Giant’ are resistant. Ornamental contorted hazelnuts are also susceptible. See General Disease Management: Bacterial Blight/Canker, Chapter 9. Infection can be reduced by mulching to prevent soil water splashing and by planting in sunny locations with good air circulation. See General Disease Management: Fire Blight, Chapter 9. Copper sprays applied for fire blight may also give some control of scab. Rake and burn, bury or compost fallen leaves and fruit. A similar fungus causes scab on other Rosaceae. See under MALUS – APPLE and CRABAPPLE. 12 • Pests of Specific Crops Nursery Production Guide
Pest Description Insects: Cotoneaster Webworm (Athrips rancidella): The moth is blackish-brown with a 12 mm wingspan. Damage is caused in late May and June by chocolate-brown larvae, up to 12 mm long. The larvae skeletonize leaf surfaces, foraging from silken webs spun on foliage and twigs. Eggs are yellowish-red and laid in June and July. CRATAEGUS - HAWTHORN Diseases: Chemical Control (rate per 100 L water; or per unit area if indicated) SEVIN T&O: 230-350 mL Apply when leaves are opening in May, and in late July and August. Crop injury may occur. Test on a small area first, before spraying the entire crop. Do not spray during bloom to avoid bee kills. Fire Blight (Erwinia amylovora): See General Disease Management: Fire Blight, Chapter 9. Leaf Spot (Fabrea Blight) (Diplocarpon mespili (Entomosporium mespili)): This is the most serious disease of Crataegus in Coastal BC. First symptoms are small, angular, reddish spots on the upper side of leaves in spring and early summer. Defoliation occurs in mid-summer. Rust (Gymnosporangium spp.): Crataegus is a common host of saskatoon rusts (see under AMELANCHIER - SASKATOON). Cedar rust is not common on Crataegus in BC except where a susceptible alternate host, such as Juniperus communis hibernica (Irish Juniper) is in close proximity. Cedar-apple rust is not known to occur in the province. Scab (Venturia inaequalis): Black leaf spots and scab on fruit. Insects: Leaf Skeletonizer (Psorosina hammondi): A yellowishgreen larva, up to 12 mm long, feeds on leaves, leaving only the veins and a thin layer of tissue behind. Rose Leafhopper (Edwardsiana rosae): The rose leafhopper is a slender, whitish-winged, sucking insect, about 3 mm long. Eggs are laid in the fall and hatch in spring. The nymphs are pale in colour and have red eyes. They suck juices out of the leaves creating a mottled effect. Premature defoliation can result. Sawfly (Pear Slug) (Caliroa cerasi): Adult is a shiny black fly with four wings. Black slug-like larvae skeletonize leaves in summer. There are two generations per season. Tent Caterpillar (Malacosoma spp.): Damage starts after buds burst. DACONIL 2787F: 250 mL DACONIL Ultrex: 150 g DITHANE DG, M-45 or WSP 80WP: 275-350 g PENNCOZEB 80WP: 275-350 g Apply when leaves unfurl in spring and every 7-14 days in wet weather. Dormant: Application of lime sulphur may help in control. See General Disease Management: Rusts, Chapter 9. No fungicides are specifically registered for this disease on hawthorn. The fungicides applied for leaf spot (see above) should give some control. Cultural Management Remove infested leaves if damage is minor. See General Insect and Mite Management: Caterpillars and Moths, Chapter 11. Rake up and burn, bury or compost fallen leaves to remove the overwintering fungus. Avoid growing hawthorns close to junipers. Rake up and burn, bury or compost fallen leaves. See under MALUS – APPLE and CRABAPPLE. See General Insect and Mite Management: Caterpillars and Moths, Chapter 11. See General Insect and Mite Management: Leafhoppers, Chapter 11. See General Insect and Mite Management: Sawflies, Chapter 11. See General Insect and Mite Management: Tent Caterpillars and Skeletonizers, Chapter 11. Nursery Production Guide Pests of Specific Crops • 13
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Page 3 and 4: Pest Description Bacterial Blight (
Page 5 and 6: Pest Description Rusts: Fungal frui
Page 7 and 8: Pest Description Mealybugs: These s
Page 9 and 10: Pest Description Insects: Mealybugs
Page 11: Pest Description CORNUS - DOGWOOD D
Page 15 and 16: Pest Description Leaf Spot (Cercosp
Page 17 and 18: Pest Description Web Blight (Rhizoc
Page 19 and 20: Pest Description Juniper Webworm (D
Page 21 and 22: Pest Description Blister Spot (Pseu
Page 23 and 24: Pest Description Insects and Mites:
Page 25 and 26: Pest Description Sydowia Blight/Tip
Page 27 and 28: Pest Description Needle Cast (Cycla
Page 29 and 30: Pest Description Sooty Mould: Black
Page 31 and 32: Pest Description Coryneum Blight, S
Page 33 and 34: Pest Description PSEUDOTSUGA - DOUG
Page 35 and 36: Pest Description Pear Trellis Rust
Page 37 and 38: Pest Description ROBINIA Diseases:
Page 39 and 40: Pest Description SALIX - WILLOW Dis
Page 41 and 42: Pest Description Berckmann’s Blig
Page 43 and 44: Pest Description ULMUS - ELM Diseas

Pests of Specific Crops

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