Susceptibility of Cydia pomonella to Bacillus thuringiensis under laboratory and field conditions

Abstract

The delta-endotoxin of 12 strains in 10 subspecies of Bacillus thuringiensis Berliner was highly active against Cydiapomonella (L.) when assayed under laboratory conditions on artificial diet. These results could not be confirmed in the field.The disappointing results obtained under field conditions are due to the behaviour of the target insect. C.pomonella larvae do not ingest food during penetration of the fruit. The larva bites pieces of the epidermis and deposits them without ingestion on top of the entry hole.

Activity of Bacillus thuringiensis δ-endotoxins against codling moth (Cydia pomonella L.) larvae

“…There is considerable discrepancy between eYcacy of Bt products under laboratory conditions and in Weld conditions, which is probably caused by the feeding behavior of the neonate larvae (Andermatt et al, 1988). Thus, an approach using expression of cry genes in transgenic plants may be the only eVective option for B. thuringiensis toxin use against codling moth larvae (Dandekar et al, 1998).…”

“…Fruit feeding by the codling moth can result in a high percentage of unmarketable fruit, since they often tunnel all the way to the core of the fruit. High quality standards of modern, conventional fruit production do not tolerate more than 1-2% of damaged apples or pear (Andermatt et al, 1988).…”

Field evaluation of Bacillus thuringiensis against lepidopterans in Norwegian apple orchards

“…Bt application against lepidopterous larvae in apple orchards has given variable results (Jaques, 1965;Andermatt et al, 1988;van der Geest, 1971;Cooper, 1984;Meadow, 1990). The potential for Bt as an insecticide in Norwegian apple orchards is probably dependent on climatic conditions.…”

Efficacy of Trichogramma evanescens and Bacillus thuringiensis var. kurstakiin control of Cydia pomonella (L.) in Turkey

“…The infestation rate was 2% on plots where only one agent was applied and 1% on the plot where both agents were applied, compared to 4% on the control plot. Intervention is considered successful if total damage is less than 2% (Andermatt et al, 1988;TAGEM, 2008). In the study, this rate of acceptable economic loss threshold was achieved on the plot where both agents were applied.…”

“…The total damaged fruit percentage (%) was assessed according to the Abbott formula (Abbott, 1925). The application was deemed successful if the rate of total spillage and total damage was less than 2% (Andermatt et al, 1988;TAGEM, 2008).…”