Mortality ofHelicoverpa zea(Lepidoptera: Noctuidae) Eggs in Cotton as a Function of Oviposition Sites, Predator Species, and Desiccation
作者:
Gregg S. Nuessly,
Winfield L. Sterling,
期刊:
Environmental Entomology
(OUP Available online 1994)
卷期:
Volume 23,
issue 5
页码: 1189-1202
ISSN:0046-225X
年代: 1994
DOI:10.1093/ee/23.5.1189
出版商: Oxford University Press
关键词: Helicoverpa zea;cotton;predation
数据来源: OUP
摘要:
Predation rates ofHelicoverpa zea(Boddie) eggs on cotton plants were determined by placing 32P-labeled moth eggs on different types of plant structures throughout the vertical strata of cotton plants. There was a slight trend for predation rates to be greater toward the top of the plants. Egg predation rates were higher on mainstem and fruiting branch terminals, and on blooms than on other plant parts. Similar predation rates (=75%) were observed on abaxial and adaxial leaf surfaces. Seasonal predation rates averaged 81.7 and 81.4 in 1982 and 1983, respectively. Rates began high each year (81.8–100%) and slowly decreased toward the end of the growing season when rates ranged from 55 to 80%. Predation by sucking predators ranged from 14.2–37.0%Orius tristicolor(White),O. insidiosus(Say),Geocoris punctipes(Say), andPseudatomoscelis seriatus(Reuter) were the most important. Chewing predators accounted for 0.8–22.9% of the predation.Solenopsis invicta(Buren) was observed removing more eggs from plants than any other predator species. Ground based predators added significantly to egg predation. Mortality rates of eggs dislodged to the soil surface were also investigated. Nearly 90% of eggs placed on the soil surface were predated in<48h. Eggs that escaped predation but that were exposed to high midday soil temperatures (e.g., 45.5°C) died of exposure. Larvae safely eclosed from eggs placed in shaded locations near the plant bases.
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