. Cooperative economic insect report. Beneficial insects; Insect pests. - 400 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES CABBAGE THRIPS (Thrips angusticeps Uzel) Econonilc Importance: This thrips has a wide range of host plants, some of which are more severely attacked than others. Several cole crops have been very seriously damaged in the seed bed in England, and local outbreaks on these crops have been reported in almost all areas of northern Europe. In addition, such crops as beets, flax, onions, peas, beans, summer grains and alfalfa have also suffered damage. In the Netherlands, Th
. Cooperative economic insect report. Beneficial insects; Insect pests. - 400 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES CABBAGE THRIPS (Thrips angusticeps Uzel) Econonilc Importance: This thrips has a wide range of host plants, some of which are more severely attacked than others. Several cole crops have been very seriously damaged in the seed bed in England, and local outbreaks on these crops have been reported in almost all areas of northern Europe. In addition, such crops as beets, flax, onions, peas, beans, summer grains and alfalfa have also suffered damage. In the Netherlands, Thrips angusticeps is considered to be by far the most important species of thrips on flax. Only two species of thrips breed on flax in the Netherlands, those being T. angusticeps and T. linarius Uzel. Damage to field crops is dependent on which generation of T. angusticeps is present. The short-winged or overwintering generation damages the young seedlings of spring crops which are not very resistant. The young plants that are not killed completely may be retarded in growth and damaged to such an extent that a reduction in yield results. Some winter crops can also be harmed by this overwintering generation. The long-winged or summer generation will infest such crops as flax, wheat, barley, rye, peas and alfalfa. In the Netherlands, larval infestations of the summer generation on flax that is grown on wheat, barley and pea stubbles is quite typical. The crop, which is not yet full grown, has a yellowish-gray color and, instead of hanging down, the tops stand up. Because the leaves assume a more horizontal position with respect to the stalks, the terminals are swollen. The top-most leaves may fall off. The growth of the flax crop is impaired so that its height falls short of that of an uninfested \ \ . \ \, \ \ , \ \ \ \. \ \ _ \ \ _ \ L-J L_J L-l U-'- 'â â' i !âi ' < l-â4â^â4â^ General Distribution of Thrips angusticeps Uzel (Thripidae, Thysanoptera) No. 143 of S
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