CRYPTOPHLEBIA-LEUCOTRETA (LEP, TORTRICIDAE) - A PROMISING ALTERNATE HOST FOR MASS-PRODUCTION OF THE CYDIA-POMONELLA GRANULOSIS-VIRUS (CPGV)FOR BIOLOGICAL PEST-CONTROL
M. Reiser et al., CRYPTOPHLEBIA-LEUCOTRETA (LEP, TORTRICIDAE) - A PROMISING ALTERNATE HOST FOR MASS-PRODUCTION OF THE CYDIA-POMONELLA GRANULOSIS-VIRUS (CPGV)FOR BIOLOGICAL PEST-CONTROL, Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz, 100(6), 1993, pp. 586-598
Cydia pomonella (L.) (Lep.: Tortricidae), the codling moth, is an impo
rtant pest particularly in apple orchards. Its larvae damage the fruit
. The granulosis virus CpGV, which originates in C. pomonella, can be
used as biological control agent of this pest with similar efficiency
like chemical insecticides. But an in vivo-production of CpGV is insuf
ficient with C pomonella, because an effective mass rearing of the hos
t is difficult. Therefore, another species of the same family, Cryptop
hlebia leucotreta, was studied for its suitability for production of C
pGV. C leucotreta was significantly better in rearing than C pomonella
: Females deposited on the average 3.9 times more eggs (504 eggs/femal
e), egg hatchability was about 10 % better (92.1 % in contrast to 82.4
%) and 10 % more of neonates (80.8 % in contrast to 70.2 %) developed
to moths under individual rearing conditions compared with C pomonell
a. In mass rearing (rearing trays: 1.8 kg diet), the best yield of mot
hs was, with 767.7 moths per kilogram (kg) diet, even 13.4 times highe
r than that with C pomonella (57.2 moths). In addition, the time for d
evelopment was nearly one third shorter, as it took only 30 (C. leucot
reta) instead of 41 (C. pomonella) days from egg to moth at 25-degrees
-C. Both species produced similar amounts of CpGV-granula per larva, w
hen 5th instar larvae were inoculated with the CpGV working-seed: 1.8
x 10(10) granula for C leucotreta and 1.7 x 10(10) for C pomonella. Th
e 10000 fold higher inoculum concentration for C leucotreta was compen
sated under simulated mass rearing conditions (Petri dish: 44 g diet)
by a 61 % higher granula yield per gram diet than that from C. pomonel
la: Maximum yield of CpGV was 6.6 x 10(9) granula against 4.1 x 10(9)
granula/g diet. Using the rearing trays, the difference in the virus y
ield should be even higher considering the higher yield of moths. In q
uality control experiments, it was demonstrated that CpGV raised in th
e homologous host C pomonella and in the alternate host C leucotreta w
as identical regarding the biological activity, the DNA pattern in res
triction enzyme analysis, the banding of granula and virions in sucros
e- and CsCl-gradients, the absorption pattern (240-360 nm) and the ele
ctron microscopic morphology of negative stained granula. These result
s showed, that C leucotreta is a promising candidate for mass producti
on of CpGV.