Fruit collapse incidence and quality of pineapple as affected by biopesticides based on Pseudomonas fluorescens and Trichoderma harzianum | Vpliv uporabe biopesticidov na osnovi bakterije Pseudomonas fluorescens in glive Trichoderma harzianum na propad in kakovost plodov ananasa

English. 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.

Slovenian. V raziskavi je bil preučevan učinek uporabe biopesticidov na osnovi vrst Pseudomonas fluorescens in Trichoderma harzianum na propad in kakovost plodov ananasa. Poskus je bil izveden kot faktorski poskus z deljenkami, kjer je prvi dejavnik obsegal dva načina vnosa patogena (pršenje in injeciranje), drugi pa naslednja štiri obravnavana: A (kontrola: brez uporabe biopesticidov), B (uporaba Bio P32 13 tednov pred pobiranjem), C (uporaba Bio T10 13 tednov pred pobiranjem) in D (uporaba Bio P32 + Bio T10 13 tednov pred pobiranjem). Inokuliran patogen je bila bakterija Dickeya zeae. Po obravnavanjih so bili določeni naslednji parametri: pojav propada plodov, vsebnost topnih snovi v plodovih in njihova celukopna kislost, vsebnost saharoze, askorbinske kisline in mineralov ter puščanje elktrolitov iz plodov. Injeciranje patogena je povzročilo večji propad plodov kot pršenje. Obravnavanji C in D sta dali najbojše rezultate z najmanjšim propadanjem plodov (pri pršenju 5 in 1,7 %, pri injeciranju 20 % v obeh primerih), veliko vsebnostjo antioksidantov (vsebnost askorbinske kisline), mineralov (kot vsebnost Ca in Mg), manjšo vsebnost elektrolitov v iztoku (v poprečju manj kot 70 % ) in bolj zdrave celične stene. Obravnavanji A in B sta bili glede na prej naštete parametre manj učinkoviti in sta pospešili propadanje plodov, posebej še pri injeciranju patogena, kar je bilo tudi bolj škodljivo glede na fiziološke lastnosti plodov. Zaključimo lahko, da uporaba biopesticidov zmanjša propadanje plodov in pozitivno vpliva na njihovo kakovost.