Flea beetle populations and economic yield of okra as influenced by nitrogen and 2, 3-Dihydro-2, 2-Dimethyl benzofuran

Nitrogen fertilisation and carbofuran applications impact plants, yet few studies examine their general impact on plant performance and plant susceptibility to insect pests and diseases when applied together. The performance of okra ( Abelmoschus esculentus L. Moench) and infestations by flea beetles in relation to nitrogen and carbofuran applications were, therefore, evaluated under a humid tropical environment. Treatments comprised of combinations of four rates of 2, 3-dihydro-2, 2-dimethylbenzofuran or carbofuran (0.0, 0.5, 1.0 and 1.5 kg ha -1) and four levels of N- fertiliser (0, 40, 80 and 120 kg ha -1). The presence of Podagrica uniformis was recorded much earlier on the plants than Nisotra sjostedti . The population of either flea beetle remained lower throughout the vegetative than the reproductive phase. While N fertilisation resulted in higher insect count than where no N was added, carbofuran at 1.0 kg ha -1 and above significantly (P<0.05) depressed the flea beetle populations up to 5 weeks after planting. Differences in the carbofuran and N interaction had no statistical significance on insect count. All cases of applied carbofuran and nitrogen increased earliness to maturity, plant height, total fruit number, fruit weight, fruit yield and net marginal returns. Higher doses of carbofuran in combination with nitrogen significantly increased earliness to plant maturity, fruit number per plant, fruit yield and net marginal returns. The best fruit yield was attained by combining 1.0 kg ha -1 carbofuran with 80 kg N ha -1, while the best economic return was achieved by combining 0.5 kg ha -1 carbofuran with 80 kg ha -1. Incidence of mosaic disease was suppressed with increasing doses of carbofuran or decreasing doses of nitrogen.La fetilisation azot\ue9e ainsi que l\u2019application du carbofuran affectent les plantes, mais peu d\u2019\ue9tudes examinent leur impact sur la performance et la susceptibilit\ue9 des plantes aux pestes et maladies, lorsque les deux sont appliqu\ue9s ensemble. La performance d\u2019Okra ( Abelmoschus esculentus L.Moench) et des infestations par des col\ue9opt\ue8res en relation avec l\u2019application de l\u2019azote et du carbofuran \ue9taient ainsi \ue9valu\ue9es sous un environnement \ue0 climat humide tropical. Les traitements comprenaient une combinaison de quatre doses de 2, 3-dihydro-2, 2- dimethylbenzofuran ou carbofuran (0.0, 0.5, 1.0 et 1.5 kg ha-1) et quatre niveaux d\u2019 engrais N (0, 40, 80 et 120 kg ha-1). La pr\ue9sence de Podagrica uniformis sur les plantes \ue9tait observ\ue9e un peu plus t\uf4t que le Nisotra sjostedti . La population de col\ue9opt\ue8res \ue9tait rest\ue9e plus basse dans la phase v\ue9g\ue9tative que dans la phase reproductive. Alors que le nombre d\u2019insects \ue9tait plus \ue9lev\ue9 dans les traitement sous fertilization azot\ue9e que dans le contr\uf4le, la dose de plus ou moins 1.0 kg ha-1 de carbofuran avait significativement (P<0.05) r\ue9duit les populations de col\ue9opt\ue8res jusqu\u2019\ue0 cinq semaines apr\ue8s le semis. Aussi, il n\u2019yavait pas eu de difference significative en terme d\u2019interaction entre le carbofuran et d\u2019azote appliqu\ue9s. Dans tous les cas, le carbofuran et l\u2019azote avait eu un effet sur la matura- tion pr\ue9coce, la hauteur de plants, le nombre total de fruits, le poids de fruits, le rendement en fruits ainsi que sur des b\ue9n\ue9fices marginaux nets. La combinaison de doses \ue9lev\ue9es de carbofurant et d\u2019azote avait affect\ue9 significativement la susceptibilit\ue9 de la plant \ue0 la maturation pr\ue9coce, le nombre de fruits par plant, le rendement en fruits et les b\ue9n\ue9fices marginaux nets. Le meilleur rendement en fruit \ue9tait realis\ue9 par la combinaison de 1.0 kg ha-1 avec 80 kg N ha-1 , alors que la combinaison de 0.5 kg ha-1 de carbofuran avec 80 kg ha-1 d\u2019azote \ue9tait la meilleure du point de vue de la rentabilit\ue9 \ue9conomique. L\u2019incidence de la maladie de mosa\uefque \ue9tait control\ue9e soit par l\u2019augmentation des doses de carbofuran ou par la diminution des doses d\u2019Azote. de carbofura

Evaluation of short duration ICRISAT pigeon pea cultivars in mixtures with FARZ-7 maize under the derived savannah conditions of Nigeria

Three ICRISAT short duration pigeon pea cultivars namely: ICPL84023, ICPL151, and ICPL87, were evaluated in intercropping system with FARZ-7 maize for growth, grain yield, and intercropping benefits at the University of Nigeria Teaching and Research Farm in the early cropping season of 1993. Intercropping any of the short duration pigeon pea cultivars with FARZ-7 maize was more beneficial than planting maize or pigeon pea sole. Although intercropping depressed grain yield of short duration pigeon pea by 20 to 58% of its sole, in terms of land equivalent ratio (LER), intercropping benefits ranged from 1.33 to 1.77, the highest being with ICPL87 + maize intercrop. ICPL151 and ICPL87 were bigger plants in intercrop with higher relative crowding coefficients (RCC) than ICPL84023. But ICPL151 and ICPL84023 were able to compete better with maize than ICPL87. The yield advantage observed with ICPL87 + maize was due to the extra yield of maize in that mixture. Maize was in all cases the dominant component of the mixture having higher relative crowding coefficient, and competition coefficient values than the pigeon pea cultivars. ICPL151 and ICPL84023 would be recommended for intercropping with maize because of their higher yield contribution to the overall yield, as the legume grain is of premium value compared with maize grain. [IJARD Vol.3 2002: 138-143