High efficacy of extracts of Cameroon plants against tomato late blight disease

Abstract

-The classical protection of tomato plants against the late blight disease caused by the fungi Phytophthora infestans involves the use of synthetic fungicides. However, such a practice raises two major issues. First, synthetic fungicides are toxic substances that are a threat to the ecosystem. Second, the efficiency of synthetic fungicides is decreasing due to the development of fungicide resistance by the fungi. In addition, there is growing concern from consumers about food contamination due to heavy reliance on toxic and persistent chemicals in plant protection strategies. Therefore, there is a necessity to evaluate the efficacy of alternative compounds. Biologically active products occur in plants for protection against pests, pathogens and other plants. Such compounds could be valuable as biopesticides for controlling plant diseases because they are biodegradable and selective in their activities. In that context, we conducted laboratory and greenhouse experiments to assess the efficacy of nine extracts of native plants of Cameroon in controlling P. infestans. Sporangial germination was determined after 24 h of incubation on 1.5% water agar medium at 18• C in the dark. Lesion size, and late blight latency and severity were assessed on 7-8-week-old detached leaflets and whole tomato plants incubated in the greenhouse for 7 days. Our results showed that Cupressus benthamii and Vetiveria zizanioides extracts were the most effective preparations, leading to 23% and 35% inhibition of sporangial germination, respectively, and to 86% and 77% disease reduction. A clear relationship between disease latency and disease severity was established. The identification of C. benthamii and V. zizanioides extracts as potential alternate compounds for late blight control is a major step in the process of replacing harmful pesticides. Using these biopesticides in combination with other established disease management practices could help control late blight in a more sustainable and environmentally friendly way. plant extracts / Phytophthora infestans / late blight / tomato / antifungal activity / disease suppression / biopesticide

In Vitro and In Vivo Effect of Poplar Bud Extracts on Phytophthora infestans: A New Effective Biological Method in Potato Late Blight Control

“…Compounds of plant extracts may have direct inhibitory effects on plant pathogens (e.g., by fungicidal or fungistatic activities), or they can help in the establishment of favorable conditions for antagonistic microbes [26]. Extracts of several plant species have been reported to be effective against P. infestans in laboratory bioassays [27,28]. Wang et al achieved 90% inhibition of some diseases including late blight in potatoes via a foliar application of 1% leaf extracts of plant extracts (Galla chinensis, Potentilla erecta, Rheum rhabarbarum, Salviae officinalis, Sophora flavescens and Terminalia chebula) [29].…”

Biopesticides and Their Role in Sustainable Agricultural Production

“…Botanical pesticides are prepared from plants and plant parts obtained from the environment, natural or man-made [198]. The materials are cleaned of dirt or foreign materials and then extracted either using solvents or distillation to obtain extracts or essential oils, respectively [199]. Production of microbial pesticides follows the same procedure as botanicals, except the that the antagonistic microorganisms are collected from sources like the cowshed, hay fields, rhizosphere, compost and manure [203].…”

A Lipidomic Analysis of Leaves of Esca-Affected Grapevine Suggests a Role for Galactolipids in the Defense Response and Appearance of Foliar Symptoms

“…Protection against GTDs relies mainly on prophylactic measures, remedial surgery [ 26 , 39 ], and the application of biological agents [ 8 , 31 ] or mixtures of fertilizers [ 40 , 41 ] to reduce symptom incidence and severity; these control strategies often offer only partial protection. One of the main concerns in agriculture today is the reduction of pesticide use [ 29 , 31 , 42 , 43 ]. Consequently, identifying resistance biomarkers is vital in attempts to define new control strategies toward sustainability.…”