Vol. 14 No. 23-37 (2023): Survey and control fungal stem rot disease of groundnut (Arachis hypogaea L.) using garlic leaf extracts (Allium sativum L.) in Adamawa State

Groundnut fungal stem rot is one of the most important limiting factors to groundnut

production and one of the most important diseases of groundnut caused by Sclerotium rolfsii

which is a destructive soil-borne fungal pathogen. The survey and control of stem rot disease

of groundnut in Adamawa State was conducted from 2017 to 2023. The research focused on

groundnut incidence and severity of stem rot pathogen, phytochemical screening of the

various garlic parts used and in vitro management of the pathogen using Leaf extracts of

Allium sativum . Samples collected from nine local government areas of Adamawa State were

taken to Plant Science laboratory of Modibbo Adama University, Yola in a dry sterile

polythene bag. Laboratory work was carried out in the Department of Plant Science and

Biotechnology. Potato Dextrose Agar (PDA) was used for the isolation and in vitro control

trials. The result for incidence of stem rot disease of groundnut from the nine Local

Government Areas of Adamawa State showed Mubi North had the highest incidence of 22.34

%, while Guyuk had the least incidence of 6.75 %. The level of stem rot disease severity

revealed that Ganye recorded the highest severity of 4.60 and Guyuk had the least with 2.40.

Qualitative phytochemical analysis reveals the presence of alkaloids, flavonoids, phenols,

steroids and terpenoids in the aqueous garlic leaf extracts. Quantitatively, alkaloids were

recorded as the highest occurring phytochemical with 6.71% while tannins were the lowest

with 1.40%. Plant extract materials were effective in inhibiting the growth of Sc lerotium

rolfsii in vitro. The level of inhibition increased with increase in concentrations. It is

therefore recommended that the use of A. sativum leaf extracts for the management of

groundnut stem rot should be encourage among local farmers at a concentration between

40-60 % because of its effectiveness, affordability and environmental friendliness.