Beneficial Insects and Mites

Table of Contents

1. Introduction
2. Predators
3. Parasitoids
4. Table 1: Common Beneficial Insects and Mites Found in Orchards

Introduction

Many orchard pests are attacked by beneficial insects or mites and by various fungal, bacterial and viral agents. Often these natural enemies provide good suppression of pest populations, especially indirect pests (e.g, aphids, mites, leafminers), defined as those that feed on or in leaves.

Predators

Natural enemies of pests in orchards include both predators and parasitoids. Predators are generally as large or larger than the prey they feed on. They are quite capable of moving around to search for their food, and they usually consume many pest insects during their lifetime. Lady bird beetles, lacewings and syrphids are examples of insect predators.

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Parasitoids

Parasitoids, or parasitic insects are smaller than their prey. One or more parasitoids grows and develops in or on a single host. The host is slowly destroyed as the parasitic larva(e) feed and mature. Most parasitic insects are wasps or flies. Adult parasitoids do not usually feed on insects, but are highly mobile, laying eggs in many hosts. Aphids, leafminers and leafrollers and other caterpillars are often attacked by parasitic insects.

Beneficial insects and mites can help prevent or delay the development of pesticide resistance in orchards by reducing the number of pesticides require to control a pest. They will also feed on the resistant pests that survive a pesticide application. Table 1 lists common beneficial insects and mites and their characteristics.

IPM programs take advantage of the biological pest control provided by beneficial insects and mites by conserving or augmenting natural enemies in orchards. When chemical controls are necessary in an IPM program, pesticides recommended are those that have minimal impact on beneficial naturally occurring in the orchard. Predatory mites are now commercially available in Ontario for release into orchards. These mites have been selected for a high degree of resistance to commonly used insecticides.

The following are some common-sense methods of conserving beneficial insects and mites in your orchard:

• learn to recognize beneficial and distinguish them from pests
• avoid using broad-spectrum pesticides
• use insecticides and miticides compatible with IPM programs
• maintain ground covers as a supply of alternate prey, pollen, nectar, and shelter for many predators and parasitoids
• monitor and record what levels of beneficials you observe in your orchard

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Table 1: Common Beneficial Insects and Mites Found in Orchards

1. Predatory Mites
2. Aphid Predators
3. General Predators
4. Parasitoids

Predatory Mites

Beneficial Name	Description	Favourite Prey	Predacious Stage	Where Found & When Active
Amblyseius fallacis (Phytoseiidae)	Clear or translucent, sometimes with brown markings on back; tear-shaped, very fast moving (0.3mm)	Phytophagous mites (e.g., European red mites, two spotted spider mites)	Nymphs, adults	Overwinters as adult under bark and at tree base. Active in ground vegetation early in season. Becomes more active in tree canopy after bloom and through growing season.
Typhlodromus pyri (Phytoseiidae)	Indistinguishable from A. fallacis to the untrained eye.	European red mites, two-spotted spider mite, apple-rust mite	Nymphs, adults	Overwinter as eggs under bark and in limb crotches. Hatch in early spring. Found in tree canopy from April to September.
Zetzellia mali (Stigmaeidae)	Bright yellow with orange marking; somewhat diamond-shaped (0.5mm).	Phytophagous mites	Nymphs, adults	Found on undersides of leaves along midribs where phytophagous mites feed.
Balaustium spp (Erythraeidae)	Large, velvety, dark red to bright red, fast moving (1mm).	Phytophagous mites	Nymphs, adults	Present on bark and leaves, noticed mainly in spring.

Figure 1. Amblyseius fallacis feeding on two-spotted spider mite.

Figure 2. Zetzellia mali feeding on mite egg.

Figure 3. Balaustium, or red velvet mite.

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Aphid Predators

Beneficial Name	Description	Favourite Prey	Predacious Stage	Where Found & When Active
Aphid Midges (Cecidomyiidae)	Larvae:small (<1.5mm), legless and bright orange. Adults:small non-descript flies that are rarely seen.	Aphids	Larvae	Larvae found in aphid colonies. When aphids are plentiful they kill more than they can eat.
Hover, or flower flies (Syrphidae)	Larvae:legless & slug-like, mottled brown and/or green (5-10mm). Adults:bee-like flies with habit of hovering in mid-air.	Aphids	Larvae	Larvae found in aphid colonies all growing season. Adults are often seen visiting flowers.
Lacewings (Chrysoperlidae Hemerobiidae)	Adults:green or brown with long slender body and membranous wings (2cm long). Larvae:alligator-like, mottled green or grey, with large sickly-shaped jaws (7-8mm). Eggs:white on long thread-like stalk.	Aphids, also mites	Larvae, adults	Eggs laid on leaves and branches. Larvae found in foliage. Present early spring to late summer.
Ladybird beetles (Coccinellidae)	Adults:oval-shaped, orange beetles with black spots (3-4mm). Eggs:yellow, barrel-shaped, & laid in clusters.Larvae:elongated with well developed legs and bright markings on a dark body (5-6mm).	Aphids, also mites and scale insects	Larvae, adults	Overwinter as adults in debris beneath trees and hedge-grows. Adults and larvae active throughout tree near prey. Active all season.

Figure 4. Cecidomyiid larva in rosy apple aphid colony

Figure 5. Adult syrphid, or hover fly

Figure 6. Syrphid eggs on leaf

Figure 7. Syrphid larva with green apple aphids

Figure 8. Adult green lacewing

Figure 9. Green lacewing eggs on leaf

Figure 10. Antlion, or lacewing larvae

Figure 11. Adult brown lacewing

Figure 12. Adult seven-spotted ladybird beetle

Figure 13. Ladybird beetle eggs

Figure 14. Larva of ladybird beetle

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General Predators

Beneficial Name	Description	Favourite Prey	Predacious Stage	Where Found & When Active
Minute pirate bugs (Anthocoridae)	Adults:small (3-4mm), black bugs with a white diamond mark on wings. Nymphs:tiny shiny orange or brown, quick moving.	Aphids, mites	Nymphs, adults	On leaves throughout growing season.
Mullein bugs (Miridae)	Nymphs:very small (1-2mm), green, with red eyes, and very active. Adults:grayish-green oval-shaped bugs (3mm long).	Mites, aphids	Nymphs, adults	On leaves especially fruit clusters or in cured shoots. Active from May to October.
Assassin bugs (Reduviidae)	Adults:large, long legged (20mm), brown with long curved beak. Abdomen may flare out beneath wing. Nymphs:similar to adults but small and without wings.	Aphids, mites, caterpillars, other soft bodied insects	Nymphs, adults	On bark and foliage of trees as well as in vegetation.
Ground beetles (Carabidae)	Large,black or brown beetles (3-20mm), shiny or dull, somewhat flattened laterally.	Many soft-bodied insects, including codling moth larvae in fallen apples	Adults	Nocturnal, found in sod, under vegetative debris, stones and logs.
Spiders	Variable in size and colour depending on species, 8 legs.	Most insects found in trees	Immatures, adults	In tree canopy and on branches and trunk.

Figure 15. Minute pirate bug

Figure 16. Mullein bug nymph

Figure 17. Adult mullein bug feeding on apple leafhopper

Figure 18. Assassin bug

Figure 19. Ground beetle

Figure 20. Arborial spider

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Parasitoids

Beneficial Name	Description	Favourite Prey	Predacious Stage	Where Found & When Active
Trichogramma wasps (Thichogrammidae)	Minute (<0.7mm) wasps that parasitize lepidopteran moth eggs.	Eggs of codling moth larvae, leafrollers	Larvae	Adults active within tree canopy. Larvae found inside eggs of host species.
Pholetesor ornigis (Braconidae)	Small black wasps (5mm) with a tiny black spot on each forewing & long antennae. Pupae are inside white, oval, pill-shaped cocoons.	Tentiform leafminer (TLM)	Larvae	Adults active within tree canopy shortly after each TLM flight. Larvae feed inside TLM larvae. Pupae found inside TLM mine.
Chalcid wasps (Chalcidae)	Small shiny wasps with short antennae and pointed abdomens.	Tentiform leafminer and other caterpillars	Larvae	Adults active in the canopy. Larvae and pupae found inside TLM mines & on various other caterpillar species.
Other parasitic wasps (Braconidae)	Small (0.5-3.6) black, black brown, orange or yellow wasps. Females.	Caterpillars of moth pests	Larvae	Adults active in tree canopy. Larvae feed inside caterpillars.

Figure 21. Trichogramma wasp parasitizing moth eggs

Figure 22. Parasitized rosy apple aphid

Figure 23. A braconid wasp

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