Application of mangosteen peel fermented solution, Trichoderma harzianum, and sodium bicarbonate mixed with potassium permanganate for fruit rot control of durian cv. ‘Monthong’

Abstract

Abstract

The study aimed to assess the growth inhibition to control fruit rot of durian cv. ‘Monthong’ caused by Lasiodiplodia sp. The samples from the symptomatic parts of the fruit with rot was collected. Lasiodiplodia sp. were then isolated from the collection and used for testing by laying out in a completely randomized design (CRD). There were 4 methods (4 treatments) in total: 1) Treatment 1 (T1) was by dipping inoculated durian fruit in the 100% concentration of mangosteen peel fermented solution; 2) Treatment 2 (T2) was by dipping inoculated durian fruit in Trichoderma harzianum in sterilized water, concentration 10⁸ spore/ml.; 3) Treatment 3 (T3) was by washing inoculated durian fruit with a 0.3% concentration solution of sodium bicarbonate mixed with potassium permanganate (KMnO4); and 4) Treatment 4 (T4) was by dipping inoculated durian fruit in sterilized water (inoculated control). The results showed that T3 was able to inhibit the growth of Lasiodiplodia sp. more than the other treatments (T1, T2, and T4). T3 showed 72% growth inhibition as fruit rot symptoms were observed on the 9^th day after incubation. Consequently, primary infection after the first exposure to the pathogen is the slowest and durian fruit had the least damage, accounting for 22% of the total fruit production. This level of damage is not considered to be an economic loss for ‘Monthong’ durian production. The said damage value was also lower by 56% than that of the inoculated control. Through correlation analysis, high growth inhibition of Lasiodiplodia sp. was associated with less fruit damage (r=-1.00). Meanwhile, both T1 and T2 were able to inhibit the growth of Lasiodiplodia sp. only with 44%, their primary infection duration was at 8 days (the symptoms of fruit rot were found on the 8^th day after inoculation), and with 44% fruit damage of the total production. Whereas T4 (inoculated control) had the fastest primary infection duration that was detected on day 6 after inoculation and maximum fruit damage equaled to 78%. It can be concluded that by washing fresh fruit of durian cv. ‘Monthong’ after harvest in the 0.3% concentration of sodium bicarbonate mixed with potassium permanganate solution (T3) before packing and transporting to a container pickup truck without air conditioning system could be a better method among others to control and delay fruit rot caused by Lasiodiplodia sp. This fruit rot control method is also found to be safe for producers, consumers, and the environment.