Reduced volume application of fungicides for the control of onion rots

Grinstein, A.; Elad, Y.; Temkin-Gorodeiski, Naomi; Rivan, Yehudith; Frankel, Harry

doi:10.1007/bf02980850

Cited by 7 publications

(3 citation statements)

References 5 publications

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“…Chemical and cold treatments can effectively control onion BM. Bulb treatment with a mixture of diethofencarb and carbendazim, thiabendazole or imazalil (Grinstein et al, 1992) or fumigation with sulfur dioxide (Thamizharasi and Narasimham, 1993) can control BM during storage. However, chemical treatment of bulbs is undesirable due to the potential health hazards.…”

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confidence: 99%

“…Infected bulbs show black discoloration on the neck, shallow lesions on the outer scales, and streaks of black mycelia and spores beneath the outer dry scales. Severe incidences of BM on onion bulbs in storage have been reported from India (Gupta et al, 1991;Maheshwari, 1988), Sudan (Hayden et al, 1994a), Israel (Grinstein et al, 1992), Egypt (Zohri et al, 1992), Australia (Salvestrin and Letham, 1994), Taiwan (AVRDC, 1999), and the United States (Ceponis, 1986). Losses can be as high as 60% during summer storage (Tanaka, 1991).…”

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confidence: 99%

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Evaluation of Onion Cultivars for Resistance to Aspergillus niger, the Causal Agent of Black Mold

Ko¹,

Huang²,

Wang³

et al. 2002

jashs

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Black mold (BM), caused by Aspergillus niger Tiegh., is a common onion (Allium cepa L.) postharvest disease under hot and humid storage conditions. This study aimed to develop a BM screening protocol, to evaluate onion cultivars for resistance. The effects of pathogen isolate, inoculum density, incubation temperature, and inoculation method on severity of BM were investigated in designing the screening protocol. Variation in virulence was observed and two highly virulent subcultures, An4-2 and An39-3, were selected for study. Disease severity, both in lesion size and sporulation degree, increased with higher inoculum densities and incubation temperatures. In contrast, small lesions and no sporulation were observed when onion scales were inoculated with 1 × 104 spores/mL or incubated at temperatures lower than 20 °C. Inoculation of onion scales or entire bulbs were compared and scale inoculation correlated better with BM incidence in storage. The procedure for BM screening protocol included: wound inoculation of onion slices with 40 μL inoculum suspension of 1 × 105 spores/mL, incubation at 25 °C with 12 hour photoperiod, and rating lesion diameter and sporulation 4 days after inoculation. Using this screening protocol, 42 onion cultivars were evaluated and cultivars with better storability such as `Red Pinoy', `Serrana', `Dehydrator No.3', and `Moonlight' were tolerant to A. niger. These cultivars showed small lesions and no sporulation during screening. On the other hand, cultivars with poor storability like `Texas Early Grano 502', `Granex 429', and `Explorer' exhibited larger lesions with profuse sporulation. Lesion diameter caused by the scale inoculation correlated significantly with bulb storage loss (r = 0.51, P < 0.01) as well as with bulb dry matter (r = -0.48, P < 0.01) and total soluble solids (r = - 0.51, P < 0.01). The screening protocol and tolerant materials are now successfully used in the Asian Vegetable Research and Development Center onion breeding program for resistance to black mold.

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confidence: 99%

mentioning

confidence: 99%

Evaluation of Onion Cultivars for Resistance to Aspergillus niger, the Causal Agent of Black Mold

Ko¹,

Huang²,

Wang³

et al. 2002

jashs

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“…and contaminated batches are disinfected. Also, after harvest, bulbs can be treated with fungicides to reduce fungal growth inside the bulbs and decrease the incidence of neck rot in storage (Ali and El Shabrawy 1979;Grinstein et al 1992).…”

Section: Controlmentioning

confidence: 99%

Peeling the onion : Unravelling the biology of fungal onion pathogens causing leaf blight,neck rot and white rot

Steentjes¹

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Botrytis squamosa, Botrytis aclada and Sclerotium cepivorum are three fungal species of the family Sclerotiniaceae that are pathogenic on onion. Despite their close relatedness, these fungi cause very distinct diseases, respectively called leaf blight, neck rot and white rot, which pose serious threats to onion cultivation. The infection biology of particularly neck rot and white rot is poorly understood. In this study, we used GFP-expressing transformants of all three fungi to visualize the early phases of infection. B. squamosa entered onion leaves by growing either through stomata or into anticlinal walls of onion epidermal cells. B. aclada, known to cause post-harvest rot and spoilage of onion bulbs, did not penetrate the leaf surface but instead formed superficial colonies which produced new conidia. S. cepivorum entered onion roots via infection cushions and appressorium-like structures. In the non-host tomato, S. cepivorum also produced appressorium-like structures and infection cushions, but upon prolonged contact with the non-host the infection structures died. With this study, we have gained understanding in the infection biology and strategy of each of these onion pathogens. Moreover, by comparing the infection mechanisms we were able to increase insight into how these closely related fungi can cause such different diseases.

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