Efficacy of Combining Varietal Resistance with Organic Fertilizer Application in Reducing Infestation of Cucumber (Cucumis Sativus L.) By Insect Pests in the Niger Delta (Published)
Efficacy of combining varietal resistance with organic fertilizer application in reducing infestation of cucumber (Cucumis sativus) by insect pests was studied during the early cropping season of 2013 at the Teaching and Research Farm, Faculty of Agriculture, University of Port Harcourt located in the Niger Delta region of Nigeria. Three varieties of C. sativus (Starke ayres, Bakker brother and Griffaton) were used for the experiment. Poultry manure (PM) was applied at four rates (4.2t/ha, 8.3t/ha, 16.7t//ha and 33.3t/ha); an inorganic fertilizer NPK 15:15:15 was applied at the recommended rate (0.3t/ha) and a control plot was also included. The fertilizers were broadcast and mixed thoroughly with soil to ensure even distribution as soon as the beds were ready and PM was allowed to cure for 14 days before sowing the cucumber seeds. Plant spacing of 50cm x 50cm and planting depth of 2-3cm were adopted with 20 plants sown per plot. The experiential land area was 18m x 14m and each treatment plot measured 2.0m x 1.5m. The experiment was laid out in a Randomized Complete Block Design (RCBD) and each treatment was replicated three times. Parameters studied included days to 50% germination and flowering, number of undamaged and damaged fruits and their corresponding weights and insects which were collected each week for three consecutive weeks (HVT 1, HVT 2 and HVT 3, respectively). The insect species were mainly in the order Coleoptera followed by Diptera, Homoptera and Orthoptera in a decreasing order. The major species collected were Epilachna chrysomellina F., Cheilomenes sulphurea Oliv., Kanahiiphaga aeneipenni Lab., Aulacopora vinula Eric., Aulacophora africana Weise, and Dinorettix africana Bol. Others included Lagria villosa F., Diopsis sp., Locris erythromela Walker, Chrysolagria sp., Lema calcrata Dalm., Planiseta sp., Coenochilus nr ventricosus Gyril, and Monolepta nigeriae Bryant. Organic manure (PM) or inorganic fertilizer (NPK 15:15:15) had no significant effect on days to 50% germination and flowering. Poultry manure applied at the rate of 33.3t/ha increased the number both of the undamaged and damaged fruits and their corresponding weights followed by plots treated with 16.7t/ha PM and the least number of fruits and weights were recorded in untreated plots (control). Higher numbers of insect pests were collected from C. sativus treated with 33.3t/ha PM and NPK. Stark ayres variety treated with 33.3t/ha PM had the highest number of fruits (155.85g) followed by Bakker brother treated with 16.7t/ha PM (142.89g) and the least was recorded in Griffaton variety that received no treatment (control). Fruit weight and number were in the order harvest 2> harvest 1> harvest 3 (HVT2>HVT1>HVT3). The study suggests that fertilizer application may lead to increased crop productivity but it may also intensify pest infestation in cultivated cucumber.