Efficacy of some chemical insecticides and plant extracts combined with Bacillus thuringiensis against Phthorimaea operculella

Phthorimaea operculella (Zeller, 1873) is one of the most damaging pests of potatoes in the world. Since the chemical pesticides play a key role in managing of potato tuber moth (PTM), the present study was conducted to assess the efficacy of Proteus®, Takumi®, Avaunt®, Dorsban®, Decis®, Consult® and Vertimec® against neonate larval penetration and one-day-old eggs of P. operculella. But adverse effects of chemical insecticides, actuated researchers to seek secure tools such as medicinal plants and biopesticides like Bacillus thuringiensis Berliner, 1715 for pest managements. Hence, we also examined toxicity of savory, ziziphora and cumin methanolic extracts against the pest under laboratory conditions. We also surveyed the synergistic/antagonistic interactions between the most effective insecticide and methanolic extract with Bt against PTM. Our results showed that both Vertimec® and savory synergized the performance of Bt against neonate larval penetration of P. operculella. Probit analysis of insecticides and methanolic extracts demonstrated that Vertimec® and Takumi® had high toxicities to the neonate larval penetration of PTM which exhibited LC50 values equivalent to 7.09 ppm and 0.008 g L−1, respectively. Savory was the most effective extract against larval penetration and hatching rate of the pest (LC50 = 440.36 and 635.93 ppm, respectively). Oviposition preference demonstrated that Vertimec® and Decis® exhibited inhibitory ovipositional effects against P. operculella.

Review: Manfaat Feromon Sek Pada Ordo Lepidoptera Untuk Pengendalian Hama Lepidoptera

Lepidoptera is one of the orders of the phylum Arthropoda Insecta class consist of butterflies that are active during the day and moths at night. Both of them belong to the order Lepidoptera and have an important role in the ecosystem. Beneficial role for plants as pollinating insects and disadvantaged role as pests of cultivated plants. An example is the fall armyworm Spodoptera sp attacking rice plants, Pteroma sp attacks sengon plants, and Helicoverpa armigera attacks red chili plants. One of the efforts to control pests is the use of sex pheromones. Several types of sex pheromones were identified, for example the sex pheromone of the cabbage leaf caterpillar Pluttela xylostella was )-11-hexadecenal, (Z)-11-hexadecenol, and (Z)-11-hexadecenyl acetate with ratio 8:18:100 and 10:1:90. Potato tuber borer (Phthorimaea operculella Zell.) sex pheromones is (E,Z)- 4,7-13 Ac (trans-4, cis-7-tridecadienyl acetate) and (E,Z,Z)-4,7,10-13 Ac (trans-4, cis-7, cis-10-tridecatrienyl acetate) with ratio 1 : 2,5. Using pheromones sex on agricultural land can significantly suppress Lepidoptera pest populations.

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

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.