Augmentation of green lacewing, Chrysoperla rufilabris, in cotton in Texas. Academic Article uri icon

abstract

  • Eggs of Chrysoperla rufilabris Burmeister (Neuroptera:Chrysopidae) were immersed in a liquid carrier and adhered to cotton foliage with a tractor-mounted applicator. In two trials, the release of 200,000 eggs per acre yielded 4,600 and 5,900 larvae per acre seven and nine days after application, respectively. The release of 400,000 eggs per acre yielded 8,100 larvae per acre nine days after application. Only the highest release rate of 400,000 eggs per acre significantly increased the number of lacewing larvae relative to plots not receiving lacewing eggs. Eclosion of C. rufilabris eggs applied with the mechanical applicator and collected from the cotton canopy was 39.5 %, while eclosion of extant eggs was 42.3 %. Densities of extant eggs in cotton averaged 2.7 eggs per 25 leaves but subsequent densities of lacewing larvae or pupae were 1,400 or less per acre where no lacewing eggs were released. Densities of cotton aphid, Aphis gossyppi Glover, were not significantly different in cotton five and eighteen days after the release of 100,000, 200,000 or 400,000 lacewing eggs per acre. Results confirm previous studies which suggest that augmentation of lacewing in cotton by the release of eggs is constrained by high mortality during the immature stages. Newly eclosed lacewing adults were released in three cotton fields at a rate often per acre on the first date and 20 per acre on two subsequent dates. During the three week study, densities of lacewing eggs were not significantly greater in fields in which adults were released relative to control fields. These results suggest that high larval mortality, adult dispersal and high cost are constraints to the use of lacewings for augmentation biological control of insect pests in cotton.

author list (cited authors)

  • Knutson, A. E., & Tedders, L.

publication date

  • September 2002