Chemigation with benomyl and fluazinam and their fungicidal effects in soil for white mold control on dry beans

Abstract

The effectiveness of fungicides in controlling white mold (Sclerotinia sclerotiorum) of dry beans (Phaseolus vulgaris) was evaluated when they were applied through irrigation water directly onto the plants or only to the soil. Two field trials were installed in April 1998 and April 1999 in Viçosa, MG. Trials were conducted as a (2 x 3) + 1 factorial: two fungicides x three application modes + one untreated control. The fungicides were benomyl (1.0 kg a.i. ha-1) and fluazinam (0.5 l a.i. ha-1). The three application modes were: (a) by backpack sprayer (667 l ha-1), (b) by garden watering-cans simulating sprinkler irrigation with 35,000 l ha-1 of water, and (c) by garden watering-cans applying water between the rows and near the soil surface in 35,000 l ha-1 of water. In 1998, fungicides were applied at 43 and 54 days after emergence (DAE); in 1999, at 47 and 61 DAE. Both fungicides were similarly effective on white mold control when applied by either chemigation or backpack sprayer, resulting in yields 21% higher than untreated control. Only fluazinam provided disease control when applications were made only in soil. Chemigation provided white mold control equivalent to that of backpack sprayer in terms of incidence, severity and number of diseased pods. Consequently, yield differences between these application methods were not significant.

Control of white mold of dry bean and residual activity of fungicides applied by chemigation

“…Moreover, greater sclerotial weight reduction was observed for fluazinam ground application. This is consistent with a previous study in which fluazinam application by backpack ground application (667 L ha -1 ) was compared to chemigation (3.5 mm) and showed that ground application reduced the weight and number of S. sclerotiorum sclerotia collected after dry bean harvest (Vieira et al, 2003). The same authors also reported that fluazinam can control white mold when applied directly to the soil surface and is superior to benomyl (systemic) in reducing incidence and severity.…”

“…Secondary infection of leaves, petioles and stems is by mycelium through direct contact with infected flowers (Abawi et al, 1975). An integrated disease management approach for S. sclerotiorum control is recommended, including use of certified seed, crop rotation with a non-host monocot crop, selection of upright cultivars, tilling soil, routine cleaning of agricultural implements, biological control, and fungicidal control (Harikrishnan and del Río, 2006;Lehner et al, 2015;McCreary et al, 2016;Miklas et al, 2013;Paula Júnior et al, 2009bVieira et al, 2003Vieira et al, , 2010Vieira et al, , 2012.…”

“…For white mold disease control in dry bean, some studies suggest chemigation facilitates better ground penetration and reduces apothecial development (Venegas and Saad, 2010) and is equivalent to fluazinam applied directly to the soil (Vieira et al, 2003). For farmers with an irrigation system already in place, application of fungicides via chemigation can save time.…”

Biological and chemical control of Sclerotinia sclerotiorum using Trichoderma spp. and Ulocladium atrum and pathogenicity to bean plants

“…The form of fungicide application (conventional application) coud be another factor to be considered when analyzing this low level of pathogen control. Oliveira et al (1995) and Vieira et al (2003) stated the importance of application know-how in relation to fungicides used to control the white mold, reinforcing the evident efficiency of fumigation and chemigation in detriment of compared to conventional application methods. …”

Biological control of the soil-borne fungal pathogen Sclerotinia sclerotiorum –– a review

“…However, in many cases, especially for high value crops or highly specialized farms these methods are insufficient. Fungicides play the most important role in successful and effective white mold management (Mueller et al 2002a;Vieira et al 2003;Paula Junior et al 2009;Derbyshire and Denton-Giles 2016). For instance, soil fumigation with metham-sodium decreased the amount of resting propagules (Ben-Yephet et al 1986).…”