Effect of Aqueous Neem Extract on Development of Pestalotia heterocornis Agent of Pestalotia Leaf Blight of Cashew in Far North Cameroon

Abstract

Cashew (Anacardium occidentale L.) trees are threatened by my many fungal diseases, among which pestaliotiopsis occupies an important place in terms of damage created in Cameroon. The aim of the present study is to evaluate the effects of aqueous extract of neem seed (AENS) on the development of Pestalotia heterocornis, the causative agent of pestalotiopsis of cashew. Isolates of P. heterocornis were obtained from diseased cashew leaves collected in the orchads. The concentrations of AENS were C1 = 500 μg/ml, C2 = 50 μg/ml and C3 = 5 μg/ml. Mancozeb 80 WP (Mz) was used as positive control. Effect of Mancobeb 80WP on the growth and spore germination of isolates were performed. The effect of AENS on the plants was evaluated in vivo. Four (4) isolates of P. heterocornis were used. AENS C1 concentration reduced the growth of all isolates. The percentage of inhibition was ranged from 45 to 90 % with the other concentrations. AENS did not inhibited spore germination (0.0 %). But Mz totally inhibited conidia germination of all isolates. In vivo, AENS protected plants against P. heterocornis. AENS can be integrated in management of cashew plants against P. heterocornis.