Plutella xylostella (L.), a menacing threat to cruciferous crops, exhibits cross-resistance to various chemical agents. The exploration of plant-derived insecticides emerges as an intervention strategy for the successful management of P. xylostella. Millettia pachyloba Drake is renowned as a traditional remedy for diverse health issues and has insecticidal properties. Experimental investigations in both laboratory and greenhouse settings utilized M. pachyloba extract (EMPE) at concentrations ranging from 2 to 10% (w/v). The objectives included inducing toxicity and controlling P. xylostella larvae effectively, assessing nutritional impacts through parameters like relative consumption rate (RCR), relative growth rate of larvae (RGR), efficiency of conversion of digested food (ECD), efficiency of conversion of ingested food (ECI), approximate digestibility (AD), and assimilation ratio (AR), and evaluating leaf damage inflicted by P. xylostella larvae on Brassica juncea. In the laboratory, the application of EMPE on P. xylostella larvae and pupae for 24, 48, and 72 hours yielded markedly higher mortality rates than the water-treated control (p < 0.05). Significant reductions in RGR, RCR, ECD, ECI, AD, and AR were evident throughout the larval stage (p < 0.05). In the greenhouse, EMPE treatments demonstrated notable differences from the water control treatment. On the 15th day of treatment, the EMPE treatment at 10% (w/v) exhibited the highest mortality rate (p < 0.05). Significantly reduced leaf damage was observed with EMPE treatments, displaying an inverse correlation with escalating concentrations. Particularly, the highest enhancement across all surveyed parameters was observed in the EMPE 10% (w/v) treatment, which was comparable to the positive control with fipronil (p > 0.05). Noteworthy differences in damage reduction percentage (DRP) were identified between EMPE contact treatments and the water control group (p < 0.05), indicating the promising potential of Millettia pachyloba extract for pest control.

Eupatorium odoratum is known for its ability to resist nematode infestations that attack the root systems of banana plants. An aqueous extract of the leaves and stems of E. odoratum (named EEOL) represents a natural solution that we investigated for its potential to control the harmful nematode, Radopholus similis, in Cavendish banana plants. Our research into EEOL’s efficacy spanned two distinct environments: a micro plot experiment model and a field model. Various concentrations of EEOL were examined to assess its efficacy in alleviating R. similis infestations and in mitigating their adverse effects on Cavendish banana plants. In the micro plot experiment model, the concentration of the original solution, diluted at ratios of 1:30×, 1 : 16×, 1 : 8×, 1 : 4×, and 1 : 2×, ranged from 1.76 to 28.16 mg · ml ^-1. In the field model, the corresponding rates varied from 6.03 to 96.54 l · ha ^-1. Key parameters, including infection rates, root necrosis indices, plant growth metrics, percentage of fallen trees, and harvest yields, were meticulously monitored and assessed. The results demonstrated that EEOL significantly reduced infection rates ( p < 0.05), decreased root necrosis indices ( p < 0.05), and promoted increased plant height, pseudostem circumference, and leaf area ( p < 0.05) in both models. Furthermore, it lowered the percentage of fallen trees ( p < 0.05) and enhanced harvest yields ( p < 0.05) in the field model. Notably, observations in the field model revealed that EEOL, particularly at a dosage of 96.54 l · ha ^-1, exhibited effectiveness equivalent to the conventional chemical nematode control method, fenamiphos ( p > 0.05). The study’s findings underscore the promising potential of EEOL in effectively managing R. similis infestations and improving the yield and quality of Cavendish banana plants. The aqueous extract of the stem and leaves of E. odoratum emerged as an effective nematode management solution for banana cultivation, in both the micro plot experiment and field conditions.