Essential Oils as Biocontrol Agents of Early and Late Blight Diseases of Tomato under Greenhouse Conditions

Abstract

Tomato production worldwide is usually restrained by various infections, among them mainly the late and early blight caused by Phytophthora infestans and Alternaria solani, respectively. Lately, there has been a growing concern over the use of synthetic fungicides on environmental and food safety, hence the need to explore other alternatives that are friendly to the user, the consumer, and the general environment. This research sought to test the potency of ginger, garlic, and Mexican marigold essential oils against the early and late blight diseases of tomato under greenhouse conditions. A synthetic fungicide (Ridomil Gold®) was used as a positive control while distilled water acted as a negative control. The extraction of essential oils was done by dry steam distillation and then mixed with tween twenty before being topped up with sterile distilled water. They were then used to spray tomato plants that had been inoculated with A. solani and P. infestans isolates under greenhouse conditions. The tomato plants were evaluated for growth, yield, and disease severity. The data obtained was subjected to ANOVA and separation of means was conducted using Student–Newman–Keul (SNK) test at 95% level of confidence. The three essential oils had a significant potency against the two diseases which is comparable to the synthetic fungicide. Marigold essential oil was also found to have a significant impact on the general growth of sprayed tomato plants. Essential oils of the three plants can be further explored as alternative products management of the two diseases.

Steps Taken to Mitigate the Threats of Maximum Residue Limits (MRL) of Pesticides in Rice and Protecting Guyana Rice Exports Markets: Present and Future Prospects

“…The results found and recommend Boom at 162 ml/ac as the most effective rates providing excellent control of the paddy bugs population and demonstrated lower levels of grain damages compared to the untreated control and were not significantly different to the Pronto (Imidacloprid) check (that has an MRLs of 0.01 mg/kg on the EU restricted list of insecticides). Similar findings were reported by [19] when these researchers evaluated three essential oils (viz. ginger, garlic, and Mexican marigold) against late and early blight caused by Phytophthora infestans and Alternaria solani, respectively and found all 3 to have significant potency against the two diseases which was comparable to the synthetic fungicide, (Ridomil Gold).…”

Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives

“…It deserves further experimentation in the control of harmful fungi. Its antimicrobial level has the potential to replace chemical pesticides or be used synergistically with chemical pesticides [25] . While exerting a high level of fungicidal ability, it can reduce the harmful effects of chemical pesticides on the soil and water source of farmland, as well as improve the yield and quality of crops, which provides a reference value for the discovery of plant‐sourced fungicides [26] .…”

Antifungal Activities of Pure and ZnO-Encapsulated Essential Oil of Zataria multiflora on Alternaria solani as the Pathogenic Agent of Tomato Early Blight Disease

“…Nanomaterials and EOs have been widely investigated for their antifungal potential in numerous reports. In particular, EOs of various medicinal plants [ Tagetes erecta L., Zataria multiflora Boiss, Melaleuca alternifolia (Maiden & Betche) Cheel] have shown beneficial antifungal effects against A. solani ( Hendges et al, 2021 ; Karimi and Meiners, 2021 ; Mugao et al, 2021 ). The antifungal properties of Fe 3 O 4 /ZnO/AgBr nanocomposites against Fusarium oxysporum Schltdl.…”