Fruit collapse incidence and quality of pineapple as affected by biopesticides based on Pseudomonas fluorescens and Trichoderma harzianum

Abstract

In this study the effect of Pseudomonas fluorescens and Trichoderma harzianum based biopesticides on fruit collapse disease incidence and pineapple quality was investigated. The experiment was implemented in a split-plot design with two factors, one involving two inoculation methods (spray and inject), and a second factor involving four treatments, A (control: no biopesticides used), B (Bio P32 from 13 weeks before harvest), C (Bio T10 from 13 weeks before harvest) and D (Bio P32 + Bio T10 from 13 weeks before harvest). The inoculated pathogen was Dickeya zeae. The incidence of fruit collapse, total soluble solids, total acidity, sucrose, ascorbic acid, mineral content, and electrolyte leakage were determined. The inject method caused more fruit collapse incidence than the spray method. Treatments C and D provided the best results having a low incidence of fruit collapse (spray: 5 and 1.7 %, inject: 20 % in both cases), high antioxidant capacity (regarding ascorbic acid), high mineral nutrient content (in terms of Ca and Mg), and low electrolyte leakage content (< 70 % in average), with a healthier cell wall characteristic. Meanwhile, treatments A and B were less efficient in these aspects and promoted the incidence of fruit collapse, especially when the inject method was used, as this was more harmful regarding the fruit physiology. In conclusion, the biopesticides employed can reduce the incidence of fruit collapse and positively affect the fruit quality.