Research Reports: Intrinsic Rate of Increase of Frankliniella Fusca (Thysanoptera: Thripidae) on Peanuts

Puche, Helena and Funderburk, Joseph

Abstract


Frankliniella fusca (Hinds) is a thrips species of economic importance that produces direct injury to leaves and is a vector of the tomato spotted wilt virus. The intrinsic growth rate of increase and the effect of two initial densities of immature F. fusca on immature survivorship and adult emergence was determined by enclosing adult or immature thrips on peanut leaflets. The number of emerging immature thrips was 14.5 per female. Immature emergence began in 7 d with a peak of emergence (67%) between 8 and 9 d. No males emerged. Females reached maturity 11.7 d after emergence. The gross value of the intrinsic growth rate of increase was 0.500 and the value determined by iteration was 0.405. Total emergence of cohorts with smaller initial numbers of immatures (32 larvae per bag) was significantly higher than of larger cohorts (117 larvae per bag). Under high population densities, reduced survivorship may assure that enough resources are available for successful reproduction of some adults. Our studies reveal that F. fusca has the potential for high population increases in peanut which may favor persistence and spread of tomato spotted wilt virus disease.

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