Abstract

ARAGON, Sandra; CANTOR, Fernando; CURE, José  and  RODRIGUEZ, Daniel. Parasitic ability of Praon pos. occidentale (Hymenoptera: Braconidae) on Macrosiphum euphorbiae (Hemiptera: Aphididae) under laboratory conditions. Agron. colomb. [online]. 2007, vol.25, n.1, pp.142-148. ISSN 0120-9965.

Praon pos. occidentale is a promising parasitoid that regulates populations of the aphid Macrosiphum euphorbiae in commercial rose production under greenhouse conditions. It was evaluated the parasitic ability of Praon pos. occidentale under three constant temperatures 18, 25 and 28ºC and varying host density 5, 10, 20, 40, 80 y 150. Each experimental unit consisted of one couple of the parasitoid with 24 hours old kept during 24 hours in graduated incubators with a 12:12 photoperiod. The number of parasitized aphids was recorded and development of the laid eggs was allowed. The instantaneous rate of search (a´) and the handling time (T_h) of the model of functional response type II were estimated. The instantaneous rate of search (a´) was higher at 18ºC with 0.1081, followed by 0.0323 at 28º C and 0.0103 at 25ºC. The shorter handling time (T_h) was 4.8913 at 25ºC, followed by 5.7579 at 28ºC and 8.2697 at 18ºC. The maximum number of parasitized aphids estimated was 4.9 at 25ºC. At 18ºC the 60% of the parasitized aphids reached the adult emergence, whereas this number was 74.2% at 25ºC and 88% at 28ºC. There was no significant effect of the host density, neither temperature on the sexual ratio of Praon pos. occidentale was recorded.

Keywords : biological control; parasitoids; aphids; functional response; commercial greenhouse crop.

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