Efficacy and Joint Action of Some Biological and Safe Agents Against the Small Land Snail, Helicella vestalis, under Laboratory and Citrus Orchard Conditions

Six pesticides of different groups i.e. Acetamiprid 20% SP, Spinosad 24% SC, Carbendazim 50 % WP, Abamectin 2% + spirodiclofen18%, Copper sulphate 25% WP and Oxamyl 24 % SL) were evaluated against the small land snail, Helicella vestalis under laboratory and citrus field conditions. Experiments were conducted at the biological laboratory of Econ. Entomol. and Agric. Zoology Dept., Fac. of Agric., Menoufia Univ. and a citrus orchard at Al Bagour locality, Menoufia governorate, during spring 2023. Results indicated that the highest mortality was recorded with all tested agents when applied at the recommendation rates (100%), while it were 40, 30, 23, 33.3, 26.7, 33.3 % for Copper sulphate, Spinosad, Abamectin + Spirodiclofen, Carbendazim, Oxamyl, and Acetamiprid, respectively, while; clove oil 3% gave mortality of 23.3% and 53% when applied at a concentration of 5%, while, the highest mortality was recorded as 100% with the concentration of 10%. The highest mortality was recorded with the binary treatments of carbendazim  + clove oil 5% and acetamiprid + clove oil 5%, when applied at half the recommended dose for each. While, copper sulphate + clove oil 5%, spinosad + clove oil 5%, abamectin + spirodiclofen  + clove oil 5% recorded 96.67%. The highest snail mortality occurred 3 weeks after application with Acetamprid (86%) and clove oil 5% (81%), while the lowest rate was recorded with Oxamyl (69.4%). In field experiments, the highest mortality was recorded with the two binary treatments: acetamiprid + clove oil 5% (86.3%), followed by the oxamyl + clove oil 5% (83.3%), while it reached 83.3%, 77.6%, 79.1%,  and 79.2% for abamectin + spirodiclofen  + clove oil 5%, spinosad + clove oil 5% and carbendazim + clove oil 5%, respectively. Finally, the treatment of copper sulphate + clove oil 5% recorded the lowest one (68.1%) after three weeks of application. The chemical analyses of clove oil proved that it contains eugenol (62.7%) as the highest component and some other phenolic compounds that have been correlated to the many-sidedness of biological aspects. This search reported  the prospective of clove oil and eugenol, as an efficient natural molluscicide replacement for its synthetic equivalent for snail control.