Straw berry Injurious Insects

A Lecture To ToT trainees

( FFS) By

Mr. Allah Dad Khan Provincial Coordinator IPM

KPK MINFAL Pakistan

A.Root-feeding Pests

The most common root-feeding pests of strawberries in Illinois include the strawberry crown borer, Tyloderma fragariae, the strawberry root weevil,Otiorhynchus ovatus, and white grubs in the genus Phyllophaga. Other below ground pests, including the strawberry rootworm, Paria fragariae and strawberry root aphid, Aphis forbesi, are rarely economically important in Illinois. Although the crown borer, root weevil and grubs are all members of the insect order Coleoptera (the beetle and weevils) their life histories differ considerably.

1. Straw berry Crown borer

Damage Strawberry corn borer

Although adults eat small holes in leaves in the fall, this defoliation rarely is economically damaging. Larval feeding is far more harmful. As one or more larvae bore downward through strawberry crowns, plants are weakened, stunted, or killed. Field borders or the portions of fields nearest older, infested plantings are often most heavily damaged

Strawberry corn borer adult and larva. Adult is about 1/3 inch (8 mm) long; larva is about 1/4 inch (6 mm) long.

2.Strawberry Root WeevilOtiorhynchus ovatus

Damage Weevil

Root weevil adults lay eggs in strawberries throughout the summer, with each female depositing 150 to 200 eggs in the soil. Eggs hatch in about 10 days, and larvae burrow through the soil to feed on roots until they mature or until cold temperatures cause a suspension of their activity. Damage to roots and crowns caused by root weevil larvae can weaken, stunt, or kill strawberry plants. Although adults eat notches from the edges of leaves, their feeding causes no economic loss.

Strawberry root weevil. Adult is about 1/3 inch (8 mm) long; larva is about 1/4 inch (6 mm) long.

3.White Grubs Phyllophaga spp

Damage White Grub

Females deposit eggs in soil during late spring or early summer; they especially prefer grass sod near wooded areas for egg-laying. As a consequence, damage caused by larvae is greatest in crops grown on sites that were grass-covered the previous season. Newly-hatched larvae feed on crop roots throughout the summer, then burrow deep in the soil to overwinter. The following year they again migrate to the root zone to feed. These larger larvae cause much greater damage than they did the year before. After overwintering again well below the soil surface, white grubs pupate early in the following summer, and adults emerge from pupal cells in the spring three years after the cycle began.

White grub adult and larva. Adults of common species range from 1/2 to 1 inch (12 - 25 mm) in length; C-shaped larva may exceed 1 inch in length

B.Foliage-feeding Pests

The foliage-feeding pests of strawberries in Illinois include leafrollers (strawberry leafroller and others), the strawberry rootworm and two mite species—the two-spotted spider mite and the cyclamen mite. This summary reviews the life histories of these pests and the practices that can be used for their management. Other foliage-feeding pests, including the grape colaspis and strawberry sawflies rarely damage strawberries in Illinois and are not covered in this paper. Information on these less common pests is summarized in Insect Pests of Strawberries in Ohio (Williams and Rings, 1980

1. LeafrollersAncylis comptana fragariae

Damage Leaf Roller

As larvae feed, they secrete silken threads to fold and tie strawberry leaflets together. Within these folded leaves, larvae feed on only the epidermis of each leaf, but entire leaflets usually turn brown.

The strawberry leafroller completes 2 or 3 generations of development each year, and moths of the summer generations are often present from July through September. Infestations may develop in spring and early summer, but they may also build up after harvest.

Strawberry Leafroller, adult and larva. Adults wingspan and larval length are about 1/2 inch.

3.SlugsAgriolimax spp. and Arion spp

Damage Slug

Slugs damage fruit by eating deep holes into the surface of berries. Slugs that damage strawberries in Illinois in the spring and early summer hatched from eggs deposited in strawberry plantings the previous fall. Conditions that favor egg-laying in the fall include the continuous presence of straw mulches. Slug survival and fruit damage in the spring are greatest in dense, wide rows and when overcast and rainy weather creates continuously moist conditions in strawberry beds.

Gray garden slug. Most slugs in strawberries range in length from 1/2 to 1 1/2 inches (12 - 36 mm).

4.Strawberry Clipper Anthonomus signatus

Damage Clipper

Adult clippers first feed on immature pollen by puncturing nearly mature blossom buds with their snouts. The female then deposits a single egg inside the bud and girdles the bud, preventing it from opening and exposing the developing larva. The adult female then clips the stem so that the bud hangs down or falls to the ground. Larvae feed within the damaged bud for a period of 3 to 4 weeks; a new generation of adults emerges in late June and July. These weevils feed on the pollen of various flowers for a short time, but seek shelter in midsummer in preparation for overwintering.

Strawberry clipper (aka strawberry weevil) Adult is 1/10 inch (2.5 mm) long.

5.Strawberry Sap BeetleStelidota geminata

Damage Sap Beetle

Their feeding leaves deep cavities in berries, and females then deposit eggs on the injured fruit. Although larvae feed in berries, they usually are unnoticed because the fruit has already begun to decompose as a result of damage caused by adults. Because over-ripe fruit is especially attractive to sap beetles, damage is often greatest in U-Pick operations where pickers leave large numbers of ripe and over-ripe berries in the field.

6. Tarnished Plant BugLygus lineolaris

Damage Bug

Several generations of this insect develop each year, and adults and nymphs are present on many different plants from April or May until a heavy frost in the fall. Tarnished plant bugs use piercing/sucking mouthparts to feed on sap from flower buds. As they feed, they inject a toxin that kills surrounding cells. This results in berries that remain small, with a concentration of seeds at the end of each ripening berry. These distorted "button berries" remain woody and unmarketable.

 Adult Tarnished Plant Bug. Length is 1/4 inch (6 mm)