Lifetable of Allotropa sp. (Hym., Platygasteridae), parasitoid of the cassava mealybug, Phenacoccus manihoti (Hom.: Pseudococcidae)
1991
Loehr, B. (Giessen Univ., (Germany). Inst. fuer Phytopathologie und Angewandte Zoologie) | Varela, A.M. | Santos, B.
Allotropa sp., a gregarious endoparasitoid of the cassava mealybug, Phenacoccus manihoti, was found in Paraguay and Mato Grosso do Sul State of Brazil. Laboratory studies on development, longevity, fecundity, and host-parasitoid relationship were made in order to assess the parasitoid's potential to control its host. Development of immature stages in a range of 20-30 degrees C was fastest at 30 degrees C. Temperature threshold and thermal constant for males and females were 17.1 and 16.7 degrees C, and 256 and 266 day-degrees, respectively. Above 20 degrees C, males developed significantly faster than females. Development in second instar hosts was slightly slower than in third instars and preoviposition adult stages. The longevity of males and females was highest at 20 degrees C (12.2 and 8.8 days, respectively). The maximum number of progeny/female was obtained at 27 degrees C and at all temperatures, female progeny outnumbered male by about 2:1, except at 35 degrees C, where the ratio was inverted. The highest intrinsic rate of increase was at 1.81 at 30 degrees C. In a range of 6-26-day-old mealybugs, the total number of progeny, number of adults/mummy and percentage mealybugs parasitized was highest in mealybugs of 12, 20 and 22 days. Up to 12 adults emerged successfully from one mummy. 12, 16, and 22-day-old mealybugs stung once by Allotropa sp. mummified at the rate of 76.5, 72.4, and 76.0 per cent respectively. Only one offspring was produced per sting
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