Fungicide resistance of Botrytis cinerea in tomato greenhouses in the Canary Islands and effectiveness of non-chemical treatments against gray mold

Abstract

Tomato greenhouses in the Canary Islands, Spain, were surveyed to estimate frequencies of resistance to benzimidazoles, dicarboximides, anilinopyrimidines and N-phenylcarbamates in Botrytis cinerea. Resistance to carbendazim, iprodione, pyrimethanil and diethofencarb was found in 74.2, 86.4, 28.8 and 31.8% of isolates, respectively. Benzimidazole- and anilinopyrimide-resistant isolates were highly resistant, showing EC50 values above 500 µg/ml carbendazim and a mean EC50 value of 28.42 µg/ml pyrimethanil, respectively. By contrast, a low level of resistance was observed among dicarboximide-resistant isolates (mean EC50 value of 1.81 µg/ml iprodione). Phenotypes with double resistance to carbendazim and iprodione, and triple resistance to carbendazim, iprodione and pyrimethanil were the most common, occurring in 36.4 and 28.8% of isolates. The surveyed greenhouses had never been treated with fenhexamid and Signum™ (pre-packed mixture of boscalid and pyraclostrobin), and baseline sensitivities of B. cinerea isolates to these fungicides were determined. The EC50 values were within the range of 0.009-0.795 µg/ml fenhexamid and of 0.014-0.48 µg/ml Signum. In addition, available formulations based on elicitors of plant defense response and biocontrol agents were evaluated against B. cinerea in tomato plants under semi-controlled greenhouse conditions, the yeast Candida sake CPA-1 being able to reduce gray mold significantly when it was applied on petiole wounds and the plants were inoculated 24 h later. Likewise, C. sake was effective against B. cinerea in harvested tomato fruits, yeast-treated tomatoes showed a 70.66 and 30.31% reduction in the diameters of decay lesions compared with controls after 10 days of storage at 20 and 9 °C, respectively.

Characterization of Egyptian <i>Botrytis cinerea</i> Isolates from Different Host Plants

“…Otherwise, the vacuma isolates had been previously reported as a predominant type in other host plants [37]. Additionally, we have found that all four isolate types, collected from different host plants, plant organs and locations, are fenhexamid-sensitive populations with a concentration between 0.013 -0.23 µg/ml indicating a fenhexamid sensitivity [48]. Thus, such fungicide concentration would be recommended as an effective fungicide against B. cinerea infections.…”

Baseline sensitivity and control efficacy of antibiosis fungicide tetramycin against Botrytis cinerea

“…With respect to fungicide resistance development, B. cinerea is considered as a classical 'high-risk' pathogen, and this complicates disease management programs (Elad et al 1992;Leroch et al 2011;Ma and Michailides 2005). Development of B. cinerea resistance to several classes of fungicides such as benzimidazoles, dicarboximides, phenylpyrroles, anilinopyrimidines, N-phenylcarbamates and succinate dehydrogenase inhibitors, has been reported worldwide (Bardas et al 2010;Elad et al 1992;Myresiotis et al 2007;Rodríguez et al 2014;Zhang et al 2009). Benzimidazole, dicarboximide and N-phenylcarbamates fungicides are no longer recommended as primary management tools because of widespread resistance of B. cinerea (Sun et al 2010).…”

New non-chemical postharvest technologies reducing berry contamination

“…It is known that B. cinerea can rapidly adapt to the environment and develop resistance, but it is susceptible to photosensitization (Luksiene, 2005;Luksiene, Paskeviciute, 2011). Benzimidazoles fungicides were introduced for plant disease control in the 1960's, but within a few years resistance emerged (Kretschmer, Hahn, 2008;Debieu et al, 2013;Rodríguez et al, 2014). Our research was carried out to test the new nonchemical measures reducing B. cinerea on berry fruits.…”

“…Our research was carried out to test the new nonchemical measures reducing B. cinerea on berry fruits. The photosensitization or volatile compound-based plant protection does not cause pathogen resistance (Neri et al, 2014;Rodríguez et al, 2014).…”