MSc.

The experiment entitled “Evaluation of the effect of mineral nutrition in the management of major pests of cowpea” was carried out with the objective to assess the effect of mineral nutrients such as potassium, calcium, magnesium, sulphur, silicon, boron, zinc and copper in the pest management of cowpea var. kanakamony. The study was conducted during two seasons viz., rainy and summer season. The data was subjected to statistical analysis to find out the effect of nutrients on management of major pest and biometric and yield parameters of cowpea.
The pot culture experiment was conducted in CRD with 12 treatments including control and absolute control with 3 replications each. The plants were raised in pots in three nutrient regimes namely, potting mixture, potting mixture + NPK and potting mixture + NPK +Ca + Mg. Later, the mineral nutrients were applied as foliar spray with 0.2% concentrated solution at different time intervals viz., the branching stage, the peak branching stage and the flower bud initiation stage. The treatments were : T1 -potting mixture (absolute control), T2 ˗P.M + one nutrient spray, T3 -P.M + two nutrient spray, T4 ˗P.M + three nutrient spray, T5 ˗P.M +NPK (control), T6 ˗P.M + NPK + one nutrient spray, T7 ˗P.M + NPK + two nutrient spray, T8 ˗P.M+NPK+three nutrient spray, T9 ˗P.M + NPK + Ca + Mg, T10 ˗P.M + NPK + Ca + Mg + one nutrient spray, T11 ˗P.M + NPK + Ca + Mg + two nutrient spray, T12 ˗P.M + NPK + Ca+ Mg + three nutrient spray.
The results of the experiment revealed that aphid infestation, pod borer infestation, pod bug infestation were significantly influenced by treatment effects. In case of aphids (Aphis craccivora), treatment T8 exhibited minimum population score on stem and pods , minimum percentage of pods and shoots infested in both seasons whereas maximum infestation was observed in T12. Treatments which received macro nutrients has shown lowest aphid score on leaves in both seasons.
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With respect to pod borers ( Maruca vitrata and Lampides boeticus), T12 recorded minimum infestation in both seasons. In summer, pod borer incidence was comparatively low and treatments which received nutrient spray were found free of borer infestation. Pod borers per plant exhibited the same trend as that of percentage of pods infested.
With respect to pod bugs, treatments T10 and T11 exhibited lowest infestation whereas T4 and T1 recorded highest pod bug infested pods in rainy and summer season respectively.
The effect of mineral nutrients on biometric and yield characters were influenced significantly in both seasons. Treatment T12 registered the highest leaf area, number of leaves, plant height and total biomass whereas T10 recorded the highest marketable and seed yield. The effect of mineral nutrients on pod length, days to flowering and fresh yield varied with seasons.
The highest K and S contents were recorded by T10 and highest Si, B and Zn was recorded by T12, T4 and T11 respectively.
On comparing the infestation caused by pests in two seasons, cowpea grown with recommended macro nutrients with foliar spray of minerals exhibited the lowest aphid (T8), pod borer (T12) and pod bug incidence (T10, and T11). From economic point of view, T10 can be recommended with respect to higher B-C ratio, highest marketable seed and fresh yield and comparatively lower infestation.