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Untersuchungen zur Bionomie und zur biologischen Bekämpfung des Kartoffelkäfers ( Leptinotarsa decemlineata Say, Col., Chrysomelidae) an zwei Standorten in Südhessen (BRD)
Author(s) -
Schrod J.,
Basedow Th.,
Langenbruch G. A.
Publication year - 1996
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.1996.tb01661.x
Subject(s) - leptinotarsa , biology , colorado potato beetle , azadirachtin , hatching , pest analysis , larva , horticulture , bacillus thuringiensis , botany , agronomy , zoology , pesticide , genetics , bacteria
Studies on bionomy and biological control of the Colorado Potato Beetle ( Leptinotarsa decemlineata Say, Col., Chrysomelidae) in Hesse (FRG) . Studies were conducted on the bionomy of the Colorado Potato Beetle at one site in Hesse (FRG), 1994. Furthermore, at another site, a field trial with natural insecticides gave answers on the efficiency of the preparations, and on the evaluation‐methods. A hatching‐rate of 79.5% from laid eggs to L 1 ‐larvae was determined. Tests on the cannibalism of eggs showed that adults destroyed up to 31% (x̄ = 19%) of the eggmasses. A clear relation between beetle density and rate of cannibalism could not be found, however. A field‐trial with a preparation of Bacillus thuringiensis var. tenebrionis (B.t.t. ; ‘Novodor’) and a Azadirachtin‐preparation (‘NeemAzal‐T’) took place. Two different concentrations per preparation and one combination showed, that an effective pest‐management with biological insecticides is possible. Due to the evaluation method, efficiency rates higher than 90% (Novodor 41/ha) and 88% (NeemAzal‐T 1.21/ha) were measured. However, the analysis of plant‐damages caused by the feeding of the beetles and larvae was also important to evaluate the efficiency of the preparations tested. A reduction to only 25% plant‐defoliation at mid‐July proved to be possible by NeemAzal (1.2 1/ha), as well as by Novodor (41/ha). The untreated plots showed 80% plant‐damage at that time. Defoliation rates at 21. July reached 93% in untreated plots, 32% with neem and 64% with B.t.t. To recognize possible long‐term effects, surviving L 4 ‐larvae were collected and observed in the greenhouse concerning their ability to pupate. While all larvae treated with B.t.t. grew up to adults like untreated larvae, neem‐treated larvae died in the prepupal stage.