Influence of certain fertilizers on the activity of some molluscicide against Biomphalaria Alexandrina and lymnaea natalensis snails

Effect of the fertilizers [ammonium nitrate, potassium sul- phate and urea] on molluscicides [copper sulphate, niclosamide and mollutox] against B. alexand-rina and L. natalensis was investigated. The molluscicides were more potant than fertilizers. Snails were exposed for 24 hr to a fertilizers using LC0 [1/10 and LC50] than, to molluscicides. Per- exposure to potassium sulphate caused a synergistic action with copper sulphate, niclosamide and mollutox on L. natalen-sis. Pre-exposure to urea caused an additive effect with niclo-samide and mollutox against L. natalensis and B. alexandrina res- pectively. Pre-exposure to ammonium nitrate caused an additive action to niclosamide on L. natalensis. Snails exposed for 24hr to one molluscicide, then exposed to fertilizers, showed that pre-exposure to niclosamide or mollutox caused an additive effect with ammonium nitrate and potassium sulphate. Pre-expo-sure to mollutox caused an additive effect with urea on the two snails' sp. Juvenile or adult B. alexandrina were ex-posed to LC0 of molluscicde-fertilizer mixture, showed that urea when mixed with each molluscicides showed greatly reduced on the growth rate percent, survival rate and snail fecundity mollus-cicides and fertilizers mixed at ratios of LC [40:10,30:20, 25:25, 20:30 and 10:40], the toxicity of the mixtures cau-sed antagonistic effect on adult B. alexandrina, but a mixture of niclosamide-ammonium nitrate caused a potent effect [syner-gism or additive] except at ratio 20:30 which showed an antago-nism on L. natalensis. Mixtures of copper sulphatepotassium sulphate [10:40], niclosamide-potassium sulphate [20:30], moll-utox-ammonium nitrate [25:25] revealed an additive effect on L. natalensis.