COLD STORAGE OF TRICHOGRAMMA PRETIOSUM RILEY (HYMENOPTERA: TRICHOGRAMMATIDAE)

ABSTRACT

The objective of this work was to evaluate the effect of storage at low temperature of Trichogramma pretiosum pupae in eggs of Sitotroga cerealella on the emergence and reproduction rates of the parasitoid. The trials were conducted in a climatic chamber at 5, 8 and 10º C, 70% R.H., constant scotophase, with 10 treatments: 4, 6, 8, 10, 12, 14, 16, 18, 20 days of storage and a control not kept in storage, all in 10 replicates. A total of 1,000 eggs containing pupae were distributed in glass tubes (10 x 3 cm), 100 of which were kept at 25° C, 70% RH and 14 h photophase (control), while the remaining ones were stored. After each storage period 100 eggs were transferred to 25º C and the emergence and reproductive capacity were observed. The T. pretiosum emergence rate was not affected by the storage time at 3 temperatures (Tukey P ≤ 0.05) and the lowest emergence rates were 85.6%, 84.5% and 77.6%, respectively for parasitoid storage at 5, 8 and 10º C. The reproductive capacity of T. pretiosum was not affected after the exposure periods in the temperatures evaluated. This result will aid in the planning of mass production, package and transport of T. pretiosum to the place of release.

KEY WORDS Parasitoid; cold storage; mass rearing; biological control