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Urena lobata is a major introduced pasture weed in Vanuatu where a biocontrol program to mitigate its impacts commenced in 2018. There was considerable uncertainty regarding the native range of U. lobata, although published literature, coupled with very simple climate matching suggested that Southeast Asia should be the most promising region in which to survey for natural enemies. We, therefore, conducted surveys for candidate biocontrol agents in Malaysia and conducted genetic matching to compare plants growing in Vanuatu, Malaysia, and other regions in the invaded and purportedly native range of U. lobata. Surveys in Malaysia prioritized a tingid bug Haedus vicarius as a promising candidate agent for the biocontrol of U. lobata and subsequent host specificity testing confirmed it is sufficiently host specific to be released in Vanuatu. Genetic matching indicated that plants growing in Malaysia are a good match to plants present in Vanuatu, validating our selection of survey sites.

Fungal infections transmitted through the soil continue to pose a threat to a variety of horticultural and agricultural products, including tomato and chilli. The indiscriminate use of synthetic pesticides has resulted in a slew of unintended consequences for the surrounding ecosystem. To achieve sustainable productivity, experts have turned their attention to natural alternatives. Due to their biodegradability, varied mode of action, and minimal toxicity to non-target organisms, plant-derived protectants (PDPs) are being hailed as a superior replacement for plant pesticides. This review outlines PDPs’ critical functions (including formulations) in regulating soil-borne fungal diseases, keeping tomato and chilli pathogens in the spotlight. An in-depth examination of the impact of PDPs on pathogen activity will be a priority. Additionally, this review emphasises the advantages of the in silico approach over conventional approaches for screening plants’ secondary metabolites with target-specific fungicidal activity. Despite the recent advances in our understanding of the fungicidal capabilities of various PDPs, it is taking much longer for that information to be applied to commercially available pesticides. The restrictions to solving this issue can be lifted by breakthroughs in formulation technology, governmental support, and a willingness to pursue green alternatives among farmers and industries.

Capsicum annuum L. is a significant horticulture crop known for its pungent varieties and used as a spice. The pungent character in the plant, known as capsaicinoid, has been discovered to have various health benefits. However, its production has been affected due to various exogenous stresses, including diseases caused by a soil-borne pathogen, Pythium spp. predominantly affecting the Capsicum plant in younger stages and causing damping-off, this pathogen can incite root rot in later plant growth stages. Due to the involvement of multiple Pythium spp. and their capability to disperse through various routes, their detection and diagnosis have become crucial. However, the quest for a point-of-care technology is still far from over. The use of an integrated approach with cultural and biological techniques for the management of Pythium spp. can be the best and most sustainable alternative to the traditionally used and hazardous chemical approach. The lack of race-specific resistance genes against Pythium spp. can be compensated with the candidate quantitative trait loci (QTL) genes in C. annuum L. This review will focus on the epidemiological factors playing a major role in disease spread, the currently available diagnostics in species identification, and the management strategies with a special emphasis on Pythium spp. causing damping-off and root rot in different cultivars of C. annuum L.

Postharvest fruits including tomatoes are commonly infected by gray mold disease resulting in significant economic losses in the fruit industry. Therefore, this study aimed to develop botanical fungicide derived from Vernonia amygdalina leaf extract to control gray mold on tomato. The emulsion formulation containing surfactant, oil carrier and water was optimized at different non-ionic alkyl polyglucoside surfactants through eleven combinations of oil to surfactant ratio (0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and 10:0 w/w). From eight selected formulations, two formulations, F5 and F7 showed stable in storage, remarkable thermodynamic stability, smaller particle size (66.44 and 139.63 nm), highly stable in zeta potential (−32.70 and −31.70 mV), low in polydispersity index (0.41 and 0.40 PdI), low in viscosity (4.20 and 4.37 cP) and low in surface tension (27.62 and 26.41 mN/m) as compared to other formulations. In situ antifungal activity on tomato fruits showed F5 formulation had a fungicidal activity against B. cinerea with zero disease incidence and severity, whereas F7 formulation reduced 62.5% disease incidence compared to a positive control with scale 1. Based on these findings, F5 formulation exhibited pronounced antifungal activity and may contribute to the development of new and safe antifungal product against gray mold on tomato.

Gray mold disease caused by Botrytis cinerea is a damaging postharvest disease in tomato plants, and it is known to be a limiting factor in tomato production. This study aimed to evaluate antifungal activities of Vernonia amygdalina leaf extracts against B. cinerea and to screen the phytochemical compound in the crude extract that had the highest antifungal activity. In this study, crude extracts of hexane, dichloromethane, methanol, and water extracts with concentration levels at 100, 200, 300, 400, and 500 mg/mL were shown to significantly affect the inhibition of B. cinerea. Among the crude extracts, dichloromethane extract was shown to be the most potent in terms of antifungal activities. The SEM observation proved that the treatment altered the fungal morphology, which leads to fungal growth inhibition. For the in vivo bioassay, the fruits treated with dichloromethane extract at 400 and 500 mg/mL showed the lowest disease incidence with mild severity of infection. There were 23 chemical compounds identified in V. amygdalina dichloromethane extract using GCMS analysis. The top five major compounds were dominated by squalene (16.92%), phytol (15.05%), triacontane (11.31%), heptacosane (7.14%), and neophytadiene (6.28%). Some of these significant compounds possess high antifungal activities. This study proved that V. amygdalina from dichloromethane extract could be useful for inhibiting gray mold disease on tomato fruit and has potential as a natural antifungal agent.