Effect of timely application of alternated treatments of Bacillus thuringiensis and neem on agronomical particulars of cabbage

Diamondback moth (DBM) Plutella xylostella is an economical pest of cabbage. Chemical pesticides constitute so far the major tool for pest management. However, the use of botanical pesticides and microbial is also considered. The objective of this study was to compare the effect of alternating treatments of Bacillus thuringiensis and Neem on agronomic particulars of cabbage as compared to solo and chemical applications. Results showed that the alternation of B. thuringiensis and Neem, performed as well as solo. Agronomic parameters were strongly related to the level of infestation of P. xylostella and other pests. The number of leaves was higher in the control and Dimethoate treatments depicting higher response to severe damages, whereas diameters of cabbage heads were higher in the Biobit and Neem treatments. There was no significant difference between the Biobit and the alternated treatment in terms of weight of cabbage. The diameter of cabbage treated with Biobit was higher than those treated with an alternated treatment. However, there was no significant difference between the alternated treatment and Neem. On the other hand, there was significant correlation between agronomic parameters and the presence of parasitoids. The correlation was significantly greater between the number of leaves, diameter and weight of cabbage in the presence of Oomyzus sokolowskii. These results indicate that timely application of alternated treatments of B. thuringiensis and Neem can be more economically viable as compared to single treatments and should be adopted in integrated pest management programs for cabbage. (Résumé d'auteur