| dc.description.abstract | Worldwide, P. marginatus causes 75% of estimated economic loss in papaya farming, with an
increase in production costs. The extract of plant essential oils (PEO) has the potential to control
P. marginatus by degrading its wax coatings to death; however, it is less studied in the East African
agroecosystem. Therefore, this study was conducted to evaluate the efficacy of four PEO from
(neem, citrus, garlic, and castor) against P. marginatus at different concentrations (0.5%, 1%, and
1.5%) with and without 0.2% adjuvants separately as a biopesticide. The experiment was con ducted in a completely randomized design with four replications per treatment concentration.
The papaya seeds (Carina variety) were used in the experiment. After 3 weeks from transplanting,
50 P. marginatus specimens were inoculated in each plant. Before treatment application, insect
abundance, leaf curling, yellowing, and soot mold were assessed. Then, 24 h, 48 h, and 72 h after
biopesticide application, insect mortality was assessed. The results showed a significant difference
(p = 0.001) for all assessment intervals in PEOs. However, for the PEOs in combination with the
adjuvants, the results were significantly different (p = 0.001) only at 24 h. It was found that
among the biopesticides, neem oil (1.5%) + isopropyl alcohol was highly effective (95.5%) after
72 h followed by (Imidacloprid (91%), citrus oil 1.5% (90.7%) and neem oil (1.5%) + paraffin oil
(81.0%). But also, there were significant differences among treatments on leaf curling, yellowing,
and soot mold reduction in papaya plants 21 days after spray. We conclude that neem oil (1.5%)
+ 0.2% isopropyl alcohol, neem oil (1.5%) + paraffin oil, and citrus oil (1.5%) significantly
controlled P. marginatus. Thus, we recommend adopting these formulations for papaya farmers to
control P. marginatus in their farms; however, simple formulations which can be easily accessed
by smallholder farmers are essential. | en_US |
