Using Green-Derived Biopolyols from Avocado Seeds for Pest Management

Abstract

Brassica crops, including collard greens, are economically important vegetable crops cultivated worldwide. Among the major pests affecting these crops, the aphids Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) are particularly relevant due to the direct and indirect damage they cause. Increasing consumer demand for sustainable agricultural practices and pesticide-free produce has intensified the search for environmentally friendly pest management alternatives. In this context, plant-derived insecticides have emerged as promising sources of bioactive compounds because of their biodegradability, selectivity, and generally low toxicity to non-target organisms and mammals. Likewise, agro-industrial residues such as avocado seeds have attracted attention as sustainable raw materials with potential bioactive and insecticidal properties. In the present study, biopolyols produced from avocado and neem seeds through a liquefaction process based on green chemistry and waste valorization principles were evaluated for their insecticidal activity against B. brassicae and M. persicae. A series of laboratory and field bioassays were conducted to assess toxicity and repellency effects on aphids. Among the tested formulations, the AAA avocado seed biopolyol (2:1/30 min) showed the highest insecticidal activity, possibly due to better preservation of bioactive compounds under the liquefaction conditions tested. Dose–response and lethal-dose (LD) analyses estimated an LD50 of 64 mg/mL and an LD90 of 429 mg/mL (p < 0.001) for the AAA biopolyol. In addition to its lethal effects, the LD90 concentration of the AAA biopolyol exhibited significant repellency against aphids and outperformed Azamax®applied at the recommended field rate. Field bioassays further demonstrated that both the AAA biopolyol at LD90 and Azamax® significantly reduced aphid abundance in collard greens of the ‘Manteiga’ cultivar under field conditions, compared to the control. Nonetheless, there was no difference in the efficacy of the AAA biopolyol and Azamax® in the field study. Altogether, these findings demonstrate the potential of seed-derived biopolyols as sustainable bioinsecticides for aphid management in Brassica crops, while also highlighting the value of agro-industrial waste as a source of novel bioactive compounds for integrated pest management programs.