PENGARUH SUHU DAN UKURAN INANG TERHADAP BIOLOGI Trichogramma sp. PARASITOID TELUR PADA Cricula trifenestrata

The experiment was conducted to study the effect of temperature and host size on the growth and development of Trichogramma sp., a species of parasitoid which attacks Cricula trfenestrata s eggs. The experiment was carried oul in the Pesl laboratory, Dalillro, Bogor. with relative humidity ranged between 60-80%. temperature ranged.between 23-25°C, 26-28°C, and 29-3 l"C. with two kinds of different egg size (big and small). This research was conducted from March lo Sepeniber 2000, to optimize the production (generation) of Trichogramma sp. in the Laboratory. The resuts showed that some of Ihe biological index of Trichogramma sp., changed when it was cultivated in different temperature and host size. Temperature influenced longivity of parasitoid while host size influenced almost all of Ihe biological index. Although it was hardly measured, however the temperature and host size seemed to have mutual support in Influencing 7}"fcAogrximnta biological index. In low temperature, the development of parasitoid was longer than that in high temperature, while parasitoid behaviour in ovipositing was influenced by egg size. On Ihe big size host, parasitoid tended ovipositing all al once, while thai on small host ovipositing was done one by one. Ihe average of Trichogramma generation on big host was 42.1 ± 17.1 with sex ratio 1 8.8 I , while thai on small host was 73.3 ± 1 3.2 with sex ratio 6.71 I , where female was plcnticr than male. By using Birch methods, it was showed that intrinsic growth rate (r„) and net reproductive rale (Ro) on big size host were lower compared with small size host while generation lime (T) on big host was longer than small host. Ro values were significantly different belween the two hosts. The result of this experiment also showed that on both host sizes, optimum value of T, Ro and rm was achieved on 26-28°C. These results arc expected to guide parasiloid breeders lo decide the temperature and host size in mass cultivating Trichogramma sp. in laboratory. While for ield application, tempeature and hosl range arc Ihe factors should be considered.

Role of host feeding niches and host refuges in habitat-related behaviour ofHyssopus pallidus(Hymenoptera: Eulophidae), a larval parasitoid of the codling moth

Parasitoid fitness depends largely on the capability to locate a host in an ecosystem. A parasitoid of a polyphagous host might not be able to find or to access the host in all its feeding niches. This study evaluated the niche selection ofHyssopus pallidus(Askew), a larval parasitoid ofCydia pomonella(Linnaeus), at the plant level with the goal of assessing its potential for biological control on different fruit crops throughout the plant cycle. Parasitoid behaviour during host location and reproduction rate were investigated on host caterpillars actively feeding on apple, pear, apricot or plum, and on caterpillars diapausing under the bark. Under laboratory conditions, the host searching behaviour ofH. pallidusvaried depending on the fruit species offered and the infestation of the fruits. Parasitoid females searched longer on apples than on other fruit species, and they searched longer on infested than on uninfested apples. Female wasps were able to locate and parasitize host caterpillars under the tree bark, and their behaviour did not vary with host accessibility. The numbers of caterpillars attacked byH. pallidusdepended on the fruit species. The highest numbers of caterpillars were parasitized in apples and apricots. Their accessibility (i.e. position) within the fruit or on the branch did not influence parasitism success. Although hosts were parasitized throughout the season, the best results were achieved with early and late releases. Therefore, the host niche selection behaviour ofH. pallidusmost likely co-evolved with the hostC. pomonellaon apples, which rendersH. pallidusa valuable biocontrol agent for successful release at different times of the season into apple orchards.