Resistência de variedades de mandioca (Manihot esculenta Crantz) a Bemisia tuberculata (Bondar, 1923) (Hemiptera: Aleyrodidae) no estado do Paraná.

Abstract

The whitefly is a major problem for cassava production in the Center-South region of Brazil due to its high potential of damage to this crop. Despite its importance, there is little information on their control. It is known that this culture is one of the few that is resistant to whitefly, mainly due to antixenosis type. However, it had not been made any studies related to resistant varieties in Brazil. Therefore, this study aims to evaluate the biology of B. tuberculata in different varieties of cassava, to identify materials with potential resistance to this pest. The biology of B. tuberculata was performed by fixing cages in cassava leaves cultivated in pots. The varieties evaluated were MEcu 72, Santa Helena, IAC-Caapora, IPR União, Caiuá and Baianinha (temperature: 25 ± 2 ° C; photoperiod: 14 hours). The evaluated parameters were duration and viability of each instar, the nymphal period and egg-adult period, longevity of females and males, fertility, sex ratio and size of females. It was prepared a fertility life table, calculated the rate of adaptation and a resistance rate. In the first study, nymphs created in the MEcu 72 variety had lower viability and the females were smaller and less longevous, with lower fertility, a lower net reproductive rate (Ro), a longer doubling time (DT) and a lower rate of adaptation, being the variety that showed the best rate of resistance. The lower fertility was obtained by the Santa Helena variety, 60% lower than in the Baianinha variety, where B. tuberculata presented best adaptation. Considering the evaluated parameters, it was concluded that the varieties MEcu 72 and Santa Helena have resistance to B. tuberculata, the IPR-União variety is moderately resistant to this pest for presenting elongation to egg-adult period, and varieties Caiuá, IAC-Caapora and Baianinha are susceptible to this pest, being in the last variety B. tuberculata has better development.