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Effects of honeydew and insecticide residues on the distribution of foraging aphid parasitoids under glasshouse and field conditions
Author(s) -
Longley Martin,
Jepson Paul C.
Publication year - 1996
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-7458.1996.tb02031.x
Subject(s) - honeydew , biology , aphid , sitobion avenae , aphididae , parasitoid , kairomone , homoptera , botany , biological pest control , agronomy , pest analysis , host (biology) , ecology
The opposing effects of attraction to host‐derived kairomones and repellency from the pyrethroid insecticide deltamethrin were investigated with aphid parasitoids from the genus Aphidius (Hymenoptera: Aphidiinae). The spatial distribution of female parasitoids was recorded in a series of experiments conducted in a small glasshouse containing wheat plants either infested with cereal aphids, Sitobion avenae (F.) (Homoptera: Aphididae), uninfested or treated with the recommended field concentration of deltamethrin. The number of parasitoids per plant were counted at 0.5 h, 1 h and then at one hourly intervals up to 8 h after release. Parasitoids showed a strong aggregation response to aphid‐infested plants compared to adjacent uninfested plants. With the introduction of insecticide‐treated plants around the aphid‐infested plants, parasitoids showed a greater tendency to disperse away, resulting in fewer parasitoids on plants and significantly lower rates of aphid parasitism. The degree of aphid fall‐off from plants was a good indicator of parasitoid foraging activity. In field studies, using sticky traps to measure the activity of parasitoids in plots sprayed with water, deltamethrin and/or an artificial honeydew solution, repellent properties were evident for up to 2 days after application. The attraction/arrestment stimuli associated with the honeydew solution were sufficient for parasitoids to continue searching insecticide‐treated areas. The implications of these findings for parasitoids searching crops contaminated with aphid‐derived kairomones and insecticides are discussed.