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Mnemiopsis leidyi, native to America, Invaded the Caspian Sea in 1999. By the end of 2000, the entire sea was accupied with them. In parallel, a sharp decline in pelagic fish such accurrred.This survey was studied the relationship between the M. leidyi and this decline. Dietary analysis was conducted on anchovy sprat (Clupeonnela engrauliformis) and M. leidyi from August 2001 to October 2002 in the coastal water in the southern parts of Caspian Sea, in Iran. M. leidyi was caught by plankton net, (the mesh size ~5 mm), at three depth at 5, 10 and 15 m . Sprat was caught by fisheries boat at Babolasar fishery harbor. Samples were not fixed in M. leidyi common fixative, 96% Ethanol were used. The Schoener index analysis reflected a similar diet composition of both species, with an critical level of overlap (>89 in Babolsar samples and >84 in Noushahar samples). This competition is one of the reasons for the decline of anchovy sprat. also, the results show M. leidyi is feeding on fish eggs, but effects of this factor on anchovy population is less than feeding competition. Controlling of M. leidyi population is reducing the pressure of its invasion and the effective approach is introduces a predator to the Caspian Sea.

Spodoptera frugiperda is a newly discovered pest in Indonesia. S. frugiperda attacks can cause crop failure and significant losses. As a preventive control measure, research was conducted to determine the most effective parasitoid in controlling S. frugiperda. This research used egg parasitoids (Telenomus remus and Trichogramma chilotraeae) and larval parasitoids (Microplitis manilae). This research was done by exposing 50 eggs of S. frugiperda each to Telenomus and Trichogramma and ten larvae of S. frugiperda to M. manilae. Ten replication was made for each treatment. The parasitism rate, parasitization rate, and progenies’ sex ratio were all observed during the experiment. The results showed that the parasitism rate of T. remus and T. chilotraeae was higher than that of M. manilae. T. chilotraeae had the lowest parasitization rate compared to other parasitoids. The sex ratio of T. remus and T. chilotraeae was also better than that of M. manila, which had more male offspring than females.