RESEARCH BULLETIN 987 APRIL, 1966 Insect and Mite Pests of Strawberries in Ohio ROY W. RINGS and R. B. NEISWANDER OHIO AGRICULTURAL RESEARCH AND DEVELOPMENT CENTER - WOOSTER, OHIO CONTENTS * * * * * * * * * * Acknowledgments__________________________________________________ 2 Introduction _______________________________________________________ 3 Relative Importance of Insect and Mite Pests ____________________________ 3 Field Key for Identification of Insects and Other Pests Attacking Strawberries ___ 3 Insects and Mites Attacking Foliage ___________________________________ 5 Strawberry Leaf Roller __________________________________________ 5 Oblique-banded Leaf Roller _____________________________________ 6 Blueberry Leaf Roller ___________________________________________ 6 Strawberry Rootworm _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 7 Grape Colaspis _______________________________________________ 8 Strawberry Sawflies____________________________________________ 9 Two-Spotted Spider Mite ________________________________________ 9 Cyclamen Mite________________________________________________ 9 Pests Attacking Buds and Fruits ______________________________________ lo Strawberry Weevi I_____________________________________________ l 0 Cutworms and Armyworms ______________________________________ 10 Strawberry Bug______________________________________________ l l Ground Beetles _______________________________________________ 11 Slugs and Snails _______________________________________________ 12 Insects Attacking Stems and Crowns ___________________________________ 12 Meadow Sp ittlebug ____________________________________________ l 2 Strawberry Crown Borer________________________________________ l 3 Strawberry Aphids____________________________________________ 14 Insects Attacking Roots ____________________________________________ 15 White Grubs ____________________ ·- _____________________________ 15 Strawberry Root Aphid __________________________________________ 16 Strawberry Root Weevils ________________________________________ 17 Summary _________________________________________________________ ls Literature Cited ___________________________________________________ 19 ACKNOWLEDGMENTS The authors express appreciation to Glenn L. Berkey, Research Center photo­ grapher, who prepared most of the photographs used in this bulletin, and to other institutions for permission to use illustrative material. The line drawings were pre­ pared by the senior author in 1941 for the first edition of this publication. 232 AG DEX 612 INSECT AND MITE PESTS OF STRAWBERRIES IN OHIO ROY W. RINGS and R. B. NEISWANDER 1 INTRODUCTION cana), and the Virginia strawberry ( Fragaria virgin­ iana). This bulletin has been prepared to aid straw­ berry growers in recognizing insect and mite prob­ When new pests of strawberries were imported lems. After a pest causing trouble is identified, either from other countries, populations rapidly built up and by the presence of one or more life stages or by its serious damage to strawberry plantings resulted. A characteristic in jury, then proper control measures good example of this is the strawberry leaf roller, may be applied. Since chemical control recommen­ which was introduced from Europe to the United States in about 1866. Control measures have been dations change from year to year, growers should ob­ tain current control recommendations from their developed and many native parasites now attack this species. So it is much less important now than it was county agent, extension specialist, or the Research 20 years ago. Center. Until recently, the most serious pests of straw­ Strawberries are native to most regions of the temperate zone. However, the large-fruited, produc­ berries were the strawberry leaf roller, the strawberry tive varieties now cultivated have been developed rootworm, the strawberry crown borer, white grubs, from a chance crossing of two species, both native to the meadow spittlebug, and the two-spotted spider ·the Americas. A Chilean species ( Fragaria chiloen­ mite. sis) was introduced into France in 1712. Later it be­ Because of a change in production practices, the came established in English gardens, where the North cyclamen mite is now one of the most serious pests of American species ( Fragaria virginiana) was being strawberries. With modern innovations such as vi­ grown. It is quite probable that a chance crossing rus-free stock, chemical weed control, and disease-re­ of these two species in England marked the beginning sistant varieties, some growers now harvest the same of commercial varieties presently used in the United beds for several years, Where plantings are main­ States. tained over relatively long periods of time, the cycla­ Strawberries are among the most important fruit men mite can be a problem of increasing concern. crops grown in Ohio and are exceeded in value only The identification of virus diseases as the cause by apples, peaches, and grapes. The most recent of "running out" and the close association of aphids figures available indicate that more than 1, 700 acres with virus transmission have increased the importance of strawberries are harvested in Ohio. Strawberries of this group of insects. Aphids injure plants in three enjoy the prestige of being the most important of the ways: ( 1 ) by sucking sap from the plant, ( 2) by in­ home-grown fruit crops. jecting toxic materials into the plant and thereby The annual income from strawberries in Ohio causing stunting or deformation of tissues, or (3) by usually exceeds $1 million. Because of the import­ acting as carriers of viruses. ance of the strawberry industry in Ohio agriculture, it is appropriate that attention be given to the more FIELD KEY FOR IDENTIFICATION important insect and other pests which attack this OF INSECTS AND OTHER PESTS crop. These pests can cause serious economic loss by ATTACKING STRAWBERRIES markedly reducing crop yields and quality. A. External Chewing Insects which Eat Holes in Leaves RELATIVE IMPORTANCE OF or Eat Large Portions of Leaves: INSECT AND MITE PESTS 1. Small greenish or bronze caterpillars which fold or roll strawberry leaves together and The majority of the insect and mite pests report­ feed within the rolled portion. ed in this bulletin are native to the United States. (Figure 3) Strawberry leaf roller Before strawberries were grown commercially, most of these pests fed upon and bred in cinquefoil ( Poten­ 2. Small holes eaten in leaves. Shiny, oval tila), American wood strawberry ( Fragaria ameri- beetles, 1/8 inch long, with four dark blotches 'Professor and Associate Chairman, Department of Zoology and on wing covers. Active only at night. Entomology, and Professor Emeritus of Zoology and Entomology. (Figure 7) Strawberry rootworm 3 3. Small holes eaten in leaves. Yellowish-brown Elongated slimy animals with or without a beetles, 3/16 inch long, with brown legs and shell. (Figure 1 7) Slugs or snails yellowish-brown antennae. Active during day. (Figure 8) Grape colaspis D. Insects Attacking Stems and Crowns: 4. Large portions of leaves eaten by green larva 1. White, frothy masses cover small, green insects with black eye spots on each side of head. which suck sap from stems. Active from Feed mostly at night. bloom to late June. (Figure 9) Strawberry sawflies (Figure 18) Meadow spittLebug B. Very Small Mites which Injure Leaves by Sucking 2. Plants stunted and small grubs in crown of Sap: plants. Larvae are white, legless grubs about 1. Leaves curled, bronzed, and sometimes speck­ 1/5 inch long. (Figure 19) Strawberry crown borer led with white. Greenish mites, almost in­ visible, present on underside of leaves. If 3. Pale yellowish or whitish aphids, without mites are numerous, silken webs appear on un­ wings, on the underside of strawberry leaves, derside of leaves. usually with their slender beaks inserted in (Figure 10) Two-spotted spider mites leaf tissue. Winged forms have a dark thorax 2. Leaves stunted and dwarfed, causing a rosette and head and a light green abdomen. of leaves due to failure of stems to elongate. (Figure 23) Strawberry aphids White to light-brown mites, almost micro­ scopic, feed on young, unfolded leaves in E. Insects Attacking Roots: crown of plant. (Figure 11 ) Cyclamen mite 1. Large, white grubs, up to 1 inch in length, with brown heads. Usually hold the body in C. Insects and Other Pests Attacking Blossom Buds and Fruits: a curved position and have distinct, well-de­ veloped, slender legs. Feed on strawberry l. Buds and newly formed fruits dried up on the roots from early spring to early fall. partly severed stems or entirely eaten. Dark, (Figure 24) White grubs reddish-brown snout beetles, from 1/12 to 1/8 inch long, make punctures in buds. Very 2. Strawberry plants lacking in vigor, foliage of small, legless, white-bodied grubs feed within a pale color, fruit drying up or failing to ma­ buds. Strawberry weevil ture properly. Roots of injured plants cover­ ed with dark, bluish-green aphids. Aphids 2. Large holes eaten into ripe or nearly ripe insert slender beaks in roots to suck sap. fruits. Large, stout caterpillars, from I to Strawberry root aphid 1-1/2 inches long, are striped, mottled, or dingy gray. Feed at night and hide beneath 3. Plants stunted, leaves closely bunched to­ debris or in soil during day. gether, dark bluish-green leaves. Small, (Figures 12-14) Cutworms and armyworms white grubs feed entirely on small rootlets of the strawberry. As larvae become larger, 3. Berries soft and