Integrated Management of Phthorimaea operculella (Zeller) Infesting Solanum tuberosum L. in Storage in MT Elgon Region, Kenya

Abstract

The production of potato, a second major staple food crop in Kenya is being constrained by an insect pest potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). The present study investigated two Integrated Pest Management techniques which would reduce (PTM) population in potato storage, four potato cultivars and two botanical quantities were used in storage in Mt Elgon region of Western Kenya. The insecticidal efficacy of Lantana camara L. and Azandiracta indica A. Jusss (Sapindales: Meliaceae) and in storage at Kapsokwony and Chemoremo villages were investigated in the present study years. In each of the studied site the experiment was laid down in randomized block Design (RBD) in a split plot arrangement at room temperature of 27 ± 2.  Four cultivars (Tigoni, Sherekea, Mayan gold and Asante) were the first factor and treatments (L. camara and A. indica leaves powder and control) as the second factor, each of which was repeated three. The room was partitioned at the center into two (3m x3m) using a PVC sheet to separate two portions for the two botanical and to prevented insect migration. We set up 4 caring bags per cultivar per botanical. We placed 2 kg PTM-free tubers per each cultivar in one caring bag hence 4 caring bags/split/ cultivar  and 16 caring bags / block, therefore the total number of caring bags  was (4 x 4)= 16 bags per cultivar hence (16 x 4) = 64 caring bags/ botanical. The splits had four 2kg caring bags hence (2x4) = 8 kg per split and (8x16) = 32kg/cultivar hence N =128kg. The caring bags were covered with a layer of the botanicals at a rate 100g, 150g, 200g, and untreated control respectively. Twenty (10♀ + 10♂) newly emerged moths were introduced inside the storage. We assessed for week one number of tubers infested and tunnels of PTM larvae, at week two for number of tubers infested and tunneling length. Week three number of tubers infested, tunneling length in tubers and number of second generation larva. Analysis was done by comparison of the means and there mean differences using R software. Results indicated use of 200g/ 2kg of the botanicals significantly reduced number of PTM larvae. Lantana camara was the most effective insecticide followed by Azadrachta indica compared to the controlled tubers. Thus the use of 200g of L. camara and Tigoni cultivar may be promising components of IPM strategies for reducing P. operculella population in potato fields and storage.