Field Assessment of Adhesion and Hatch ofChrysoperlaEggs Mechanically Applied in Liquid Carriers

• Published in: Biological control Vol. 14; no. 3; pp. 159 - 167
• Main Authors: Wunderlich, Lynn R, Giles, D.Ken
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-1999
• Subjects: biological control; Chrysoperla rufilabris; green lacewing; mechanical; release; vineyard; vineyard; mechanical; biological control; Chrysoperla rufilabris; green lacewing; release
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1006/bcon.1998.0686

A mechanical technique was evaluated for releasing green lacewing eggs in liquid suspensions. Deposited eggs were enclosed within a circle of nonpoisonous adhesive to protect them from predation and to prevent escape of hatched larvae. Released eggs were monitored daily for 5 days after release by measuring three response variables: adhesion rate of eggs to foliage, hatch rate of eggs, and “yield” of larvae from discharged eggs; “yield” was the product of egg adhesion and egg hatch. Factors tested were: egg conditioning prior to release (incubated or refrigerated), carrier (distilled water or commercial carrier solution), application technique (mechanical or hand application), and row facing (North or South). Release technique did not significantly effect egg hatch on any day. Conditioning eggs prior to release had the greatest effect on hatch of eggs and resulting yield of larvae during the 5-day monitoring period. Carrier had a significant effect on adhesion of eggs to leaves and hatch of eggs. Commercial carrier solution increased egg adhesion but decreased egg hatch compared to water. Overall mean yield of larvae from incubated eggs distributed mechanically was not significantly different for eggs suspended in water (36.4% on day 5 post-release) and for eggs suspended in commercial carrier solution (36.1% on day 5 post-release). Hand-applied eggs had a higher hatch and subsequent yield of larvae than mechanically released eggs; however, the hand technique was labor intensive.