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• Efficacy of selected botanical extracts against Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) on tomato

  31-36.

  Daniel Kepha Nabutse

  Mwanarusi Saidi

  Joshua Ogweno

  Views:

  524

  Tuta absoluta Meyrick, also known as the tomato leaf miner, is a destructive pest that feeds on tomato plants, causing significant economic losses to tomato farmers globally. Traditional methods of controlling Tuta absoluta involve the use of synthetic pesticides, but these methods have drawbacks such as environmental pollution, development of resistance by the pest, and negative effects on non-target organisms. As a result, there is a growing interest in the use of botanical extracts as alternative and safer pest control options. Three bioassay experiments were conducted to test the insecticidal, antifeedant and repellency effects of botanical extracts on Tuta absoluta. The experiments were conducted as completely randomized design (CRD) with three (3) replicates. There were eleven treatments; pyrethrum, neem, warbugia, each at different concentration levels of (8%, 10%, 12%) and controls positive (Indoxacarb 150g/L) and negative (distilled water). In all the bioassay conducted, the effects of all treatments increased over time, except for distilled water control. Synthetic chemical Indoxacarb exhibited significantly stronger insecticidal properties compared to neem, warburgia and pyrethrum extracts. Application of neem at 8%, 10% and 12% and pyrethrum at 12% had higher antifeeding effect on Tuta absoluta compared to the other treatments while warburgia at 8% concentration and indoxacarb had the lowest repellency effect compared to the other plant extracts.

• Effects of irrigation frequency and repellent plants on false codling moth (Thaumatotibia leucotreta) infestation, growth, yield, and quality of sweet pepper (Capsicum annuum L.)

  34-40.

  L. Ochari

  S. Nyalala

  M. Saidi

  Views:

  93

  Sweet pepper (Capsicum annum L.) is an important vegetable and spice crop grown worldwide for its pungency, which is derived from high concentrations of capsaicinoids. Despite the economic importance of sweet pepper as an export vegetable in Kenya, its production is currently constrained by the false codling moth (FCM) (Thaumatotibia leucotreta) and inadequate management strategies for the pest, among other factors. This study, therefore, evaluated repellent plants (Artemisia (Artemisia absinthium), Lavender (Lavandula angustifolia), and Spearmint (Mentha spicata) under different irrigation frequencies to control FCM. A split-plot factorial greenhouse experiment was conducted at Kenya Agricultural and Livestock Research Organization, Muguga (trial 1) and the Horticulture Research and Teaching Field, Egerton University, Kenya (trial 2). Irrigation frequency at three levels (irrigating once a week, irrigating twice a week and irrigating thrice a week) was the main-plot factor, while repellent plants at four levels: sweet pepper (Capsicum annum L.), artemisia (Artemisia absinthium), lavender (Lavandula angustifolia) and spearmint (Mentha spicata) constituted the sub-plot factor. Irrigating thrice or twice a week and using lavender as a repellent plant significantly reduced false codling moth infestation by 90%, increased yield by 28% and improved fruit quality in terms of fruit collar diameter and total soluble salts (TSS). The findings demonstrate that integrating lavender repellent plants with frequent irrigation can be adopted as an eco-friendly management strategy for FCM and enhancing sweet pepper yield and quality.