EVALUATION AND IMIPLEMENTATION OF NOVEL AND ENVIRONMENTALLY SAFE APPROACHES IN IPM PROGRAMME FOR TERRESTRIAL SNAILS

Abstract

Several laboratory and field experiments were conducted to study the role of certain ecologicaL biological and toxicological aspects in determining integrated management approaches on terrestrial snail pests aiming to achieve the least impact on ecosyst ms, stability and natural bala.il.ce. The obtained results could be Sll.ITI!rulrized as follow :

1- Eobania venniculata and Monacha obstructa were common on field crops, vegetable crops and ornamental plants in most districts at Sharkia, Dakahlia and Kafr El-Sheikh governorates. The malacophagous insects, Megaselia scalaris was associated with M obstructa and E. vermiculata in the three tested governorates, whereas with Cochlicella acuta in El-lbrahimia (Sharkia) and Biela (Kafr El­ Sheikh); while with Helice /la vesta/is only in Belbies. Also, Parasarcophaga pharonis with E. vermicuiata in Zagazig, Sharkia governorste. The population density of M obstructa obviously increased during spring months (March, April & May) as compared with population density during winter and autumn, the infestation did not appear in summer months. 2-Both low and high temperature degrees, soil moisture have a lethal effect on newly hatching, juveniles and adults of the two land snails. At 20°C, 75-80 % R.Ii, 12 h darkness, and mixture soil (clay+ sand), the two tested snails recorded the highest hatchability and the lowest incubation period. The variation in growth pattern of snail weight and number of eggs considerably differed according to tood type and snail species. Also, the highest hatchability percentage, and the shmtest incubation period were on lettuce and cabbage. 3- Mortality percentage and snails activity considerably differed according to snail species, year seasons and time elapsed without feeding. 4- The predational potential of either rodent or fiog species noticea bly in creased with young ages and snail::. with sm11U sizes.

5- Using plant as traps surrounding the field to connol the target snails nearly abated the population to the hal£ On the other hand, the tillage process and hand collection of snails were a useful simple process fer controlling land snail<:;. M obstnwta was the most sensitive species for B.t k, B.t.i. and Vertimec compounds than the other two sp ecies, dther applied as residue film or leaf-dipping technique. As for the molluscicidal and antifeedant effects of some plant extracts against E. vermiculata, M obstructa and T. pisana, in laboratory, data showed that neem, spotted gum ethanol achieved the most bioactivity, followed by oshar. All tested plant extracted by ethanol solvent exhibitd a higher toxicity than those of hexane. Also, residue film technique showed superior toxicity than leaf-dipping. All plant extracts by ethanol exlnl>ited high autifeedant effects, while those ofhexane failed to gain satisfactory performance. 6- Copper sulphate, fenitrothion and metaldehyde, proved to be the most toxic agent for the tested snail species. Generally, Monacha obstructa was more sensitive for all tested compounds used than the other two snail species.