The egg parasitoid Telenomus busseolae Gahan is the most important parasitoid of sugarcane pink borers and plays an important role in the suppression of their populations in Iran. To understand the efficiency of T. busseolae parasitizing Sesamia cretica Lederer, in this study, the functional response of the parasitoid was investigated at different temperatures (20, 25, 30 and 35 °C). The results of logistic regression indicated a type III functional response at all the temperatures. Roger's random parasite equation fitted the observed data at 30 and 35 °C, but Holling's disc equation fitted the data better at 20 and 25 °C. The attack rate of T. busseolae ranged from 0.0036 to 0.2148, 0.00017 to 0.1031, 0.0049 to 0.2952 and 0.0006 to 0.0382 per h, and the estimated handling time was 0.80, 0.48, 0.32 and 0.13 h at 20, 25, 30 and 35 °C, respectively.

Surveys for population densities of the maize borer Sesamia eretica Led. (Lepidoptera: Noctuidae) were conducted for three consecutive years (1997–1999) in several localities of the Nile delta in Egypt, in order to get a better insight into the population dynamics of the pest and to propose rational basis for its biocontrol using a recently isolated granulovirus. High population densities (more than one borer per plant) were observed only in the first plantings after winter (first fortnight of April). After this peak, populations almost vanished until the end of the crop season (September-October) when a slight increase was observed (0.1 borer per plant). The drastic decrease in population densities in plantings from the end of April occurs because most final instars of the borer leave the plant to pupate in the soil. This behaviour, uncommon in maize borers, results in a very high mortality rate due mainly to pupal parasitism. Only the few larvae pupating in the stem, which are much less parasitised, give rise to adults. Spatial distribution was studied using Taylor's power laws which enabled the elaboration of enumerative sampling plans for eggs, small larvae (1st and 2nd instars) and older ones. Fixed optimal sample size and sequential sampling plans for different precision levels were developed. The precision of the estimated sample size was checked using resampling of some of the data that were not used to build the models. The validation study showed that the plans were suitable for the entire Nile delta region.