Effect of plant spacing on the density of cucumber insect pests on two cucumber (Cucumis sativus L.) varieties

Abstract

A field experiment was conducted in 2017 and 2018 planting season to establish the best plant spacing that provides optimal control of  cucumber insect pests. The experiment was laid out in a split-plot design fitted into Randomized Complete Block Design with three  replicates, consisting of two main plots: Market-More and Poinsett cucumber varieties, and four sub-plots: 0.75 m x 0.75 m, 0.5 m x 0.5 m,  0.5 m x 1 m and 1 m x 1 m plant spacings. Cucumber spacing or jointly with cucumber variety significantly influenced the densities of  insect pests, insect-induced damage, and yield in 2017 and 2018, respectively. Populations of Aulacophora foveicollis, Aulacophora nigripennis, Aulacophora hilaris, Epilachna chrysomelina and Bactrocera cucurbitae were reduced in cucumber planted at 1 m x 1 m.  However, the highest insect population was recorded when cucumber was planted at 0.5m x 0.5m. Conversely, a significantly lower  insect-induced damage and enhanced fruit yield were observed at 1 m x 1m compared to other spacings. The highest fruit yield (7.24 t/ ha) was observed on Poinsett variety in 2018. Hence, Poinsett variety of cucumber should be planted at 1 m x 1 m for effective  management of insect pests of cucumber.