Abstract
ABSTRACT The cryopreservation of noctuid eggs in liquid nitrogen has proved be a promising tool in the mass production of Trichogramma, however studies into this technique have only just begun. This study evaluated the response of different densities of the female of Trichogramma pretiosum Riley to the parasitism of Mythimna sequax eggs stored and not stored in liquid nitrogen, and the performance of females reared only in cryopreserved eggs. The study evaluated the influence of the number of T. pretiosum females (4, 8 and 12) released to parasitise 40 M. sequax eggs, stored and not stored for 15 days in liquid nitrogen, as well as the performance of T. pretiosum females reared in eggs stored for three generations and females reared in non-stored eggs. Parasitism by T. pretiosum in stored eggs was 84%, twice the value obtained in previous studies. The emergence of parasitoids was greater than 95% in both experiments. The performance of females raised in stored eggs did not differ from that of females raised in non-stored eggs. The data show that the technique of cryopreservation of M. sequax eggs may be a viable alternative in the mass production of T. pretiosum.
Highlights
Egg parasitoids of the genus Trichogramma Westwood are the most frequently used agents in programs of biological control of lepidopteran pests in several countries (PEREIRA et al, 2004)
The present study evaluated the response of different densities of T. pretiosum females to the parasitism of eggs of M. sequax stored in liquid nitrogen, and the performance of females obtained from eggs stored for three generations, compared to females obtained from eggs that had not been stored
The second experiment evaluated parasitism by T. pretiosum females reared on eggs stored in liquid nitrogen for three generations (TPLN), and females reared in non-stored eggs (TP)
Summary
Egg parasitoids of the genus Trichogramma Westwood are the most frequently used agents in programs of biological control of lepidopteran pests in several countries (PEREIRA et al, 2004) Their mass production is generally carried out using eggs of microlepidoptera, such as Anagasta kuehniella Zeller, Sitotroga cerealella Olivier and Corcyra cephalonica Staiton, as they have low production costs (PARRA, 1997). These hosts produce eggs of reduced size (CÔNSOLI; KITAJIMA; PARRA, 1999), which result in small and less vigorous parasitoids when compared to parasitoids from larger host eggs due to the greater availability of nutrients for the immature insects (BAI et al, 1992; SALT, 1941). The present study evaluated the response of different densities of T. pretiosum females to the parasitism of eggs of M. sequax stored in liquid nitrogen, and the performance of females obtained from eggs stored for three generations, compared to females obtained from eggs that had not been stored
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