No abstract

Background The negative effect of over-reliance on the use of synthetic pesticides have led to the search for natural alternatives to pest control. This study was designed to evaluate the toxicity effect of the crude plant extracts of Jatropha (Jatropha curcas Linn.) seeds in comparison with methomyl on some histopathological changes of the terrestrial snail species Monacha obstructa (Pfeiffer, 1842). The toxicity effect of methomyl and crude extracts of ethanol and acetone extracts of Jatropha curcas seeds were determined on some histological changes of the land snail, Monacha obstructa at four concentrations using the contact technique under laboratory conditions. Results The results revealed that the crude extracts of Jatropha exhibited obvious adequate effects compared with methomyl against M. obstructa land snails. The highest toxicity effects were obtained by methomyl followed by the ethanolic extract of Jatropha and hexane extract of Jatropha. The histopathological effect of LC50 of Jatropha crude extract and methomyl on the digestive gland and foot tissues were examined in the land snails M. obstructa. The treated snails showed several histological changes in the digestive gland and foot compared with the control group snails. The histological examinations of the digestive tubules included destroyed and detached in the outer layer covering digestive tubules. In addition, marked increase in the width most of the digestive tubules lumen. The intertubular connective tissue between the digestive tubules showed great destruction, while the foot of treated snails showed rupture of the epithelium covering the foot and desquamation of the epithelium. We also observed the presence of areas of connective tissue necrosis and destruction of the muscular tissue. Conclusions It has been found that extracts of Jatropha seeds have a toxic activity that caused histopathological damage that led to the death of land snails, and thus it can be recommended as a source for the development of molluscicides. Graphical Abstract

No abstract

Biotic interactions among the earthworm, Allolobophora longa, fungus, Fusarium oxysporum and the root-knot nematode, Meloidogyne javanica infecting eggplant solanum melongena cultivar balady were studied under green house conditions . Multiplying nematode in all trials at the added earthworms was significantly lower than in the control (check). The highest of numbers of galls per root system and rate of nematode reproduction on eggplant were found in treatment nematode of alone, followed by treatment of M. javanica +F. oxysporum .The highest percentages of reductions in length and fresh weight of shoots and roots occurred on eggplant treated by M. javanica + F. oxysporum, M. javanica + F. oxysporum +15worms of Allolobophora longa where the values were close. The increase was only in fresh weight shoot with treatment F. oxysporum + 5worms of A. longa while the increase were in both length and fresh weight shoot with treatment 10 worms of A. longa . The highest percentage value of severity was detected by treatment of nematode + fungus . But, the lowest of severity was found in treatment of F. oxysporum +10 worms A. longa.

Laboratory bioassays were conducted to determine the effects of seven insecticides and three nematicides on penetration , infectivity and reproduction of the infective juveniles (IJs)of entomopathogenic nematodes Heterorhabditis bacteriophora and H. indica nematode species. In penetration assay, results of tested seven insecticides i.e. abamactin, Bacillus thuringiensis B.t. as bioinsecticides, chloropyrifos, chloropyrifos-methyl, esfenvalerate, methomyl and profenfos as chemical insecticides on both of entomopathogenic nematodes, indicate that the more pesticides events for reduction in average numbers of IJs nematodes penetrating last instar larvae of Spodoptera littoralis was chloropyrifos-methyl and methomyl at 100% reduction comparing with control. While the more pesticides compatible with tested nematode species are abamactin and B.t on the three tested rates of application. In infectivity and reproduction assays, three nematicides has been tested i.e. aldicarb , ethoprophos and cadusafos at three rates of application after four periods of exposure soil to tested nematicides at one day, one week, two weeks, three weeks. Results show that, the most compatible nematicides with H. bacteriophora are cadusafos in both assayes production and efficiency against Galleria mellonella larvae comparing with control, while other pesticides tested is not compatible with this nematode where the aldicarb at percentage 100% reduction in events insect larvae death, as well as test production by day, week, 2 weeks. Overall, results indicate the feasibility of an integrated use of these nematode species and chemical pesticides in crop protection.