The Effectiveness of Carapa Guianensis and Azadirachta Indica extract against Alternaria Solani in Solanum Lycopersicum (Tomato Plants)

Ronique James, Kaslyn Holder-Collins and Oceana O’Dean

📃• URC22 Abstract • 

Published: May 16, 2022Book of Abstracts of the 4th Undergraduate Research Conference. University of Guyana, Office for Undergraduate Research.

Ronique James ✉️ Kaslyn Holder-Collins Department of Biology. Faculty of Natural Sciences. University of Guyana-Turkeyen Campus. Greater Georgetown, Guyana.

Oceana O’Dean Biological Control Laboratory. National Agricultural Research and Extension Institute (NAREI). Mon Repos, East Coast Demerara.

The antifungal effects of Carapa guianensis (Crabwood) and Azadirachta indica (Neem) oils at specific concentrations of 0.25%, 0.5%, 1.0% v/v and chemical fungicide COBACK at the manufacturer’s recommended dose for the treatment of Early blight, on the mycelial growth of Alternaria solani from Solanum lycopersicum (tomato plants) under in vitro conditions were assessed using the randomised experimental design, employing the poisoned plate method. The mean inhibition percentage obtained by COBACK at 100 ppm (rec. dose) was 60% inhibition, while Crabwood and Neem oils produced inhibition percentages of 48% and 36% at 0.25% v/v, 56% and 37% at 0.50% v/v, and 56% and 42% at 1.00 % v/v respectively. There was no significant statistical difference among the inhibition potentials of the various concentrations of Crabwood oil (F(3,11)=0.19, p=0.9) and Neem oil (F(3,11)=2.18, p=0.16), and the chemical fungicide at the manufacturers recommended dose (100ppm). A weak positive correlation was evident between the various concentrations of both the Crabwood oil, r(10)=0.18, p=0.55, and Neem oil, r(10)=0.50, p=0.09; and inhibition percentages of the fungus. These results demonstrate that the oils were effective in inhibiting the mycelial growth of A. solani at all concentrations observed in comparison to the positive control. The inhibitory effect of the essential oils had no statistical difference to that of the positive control, COBACK, the chemical fungicide used in the management of A. solani at the manufacturer’s recommended dose of 100 ppm. This study aims to popularise the implementation of non-chemical alternative treatments for plant diseases by reducing the use of chemical treatments that may result in resistant plant pathogens, while adding to studies and practices related to sustainable agriculture.

Keywords: Antifungal effects, Fungicide, Alternaria solani, Carapa guianensis (Crabwood), Azadirachta indica (Neem)

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The 4th Undergraduate Research Conference (URC22) was hosted by the University of Guyana’s Office for Undergraduate Research on May 18-20, 2022.