Sustainable broadleaf weed control in cucurbit crops
Weeds are a significant problem for many Australian cucurbit producers (including in pumpkins, melons, cucumber, and zucchini), given the sprawling nature of cucurbit vines and the lack of registered herbicides suitable for selective control of broadleaf weeds.
This project, funded by Horticulture Australia Limited (HAL), was a first step in identifying the impact of weeds in cucurbit production, and areas in which weed control may be improved.
Weeds have a significant impact on cucurbit crop yield and quality, making crop management problematic. Significant weeds include fat hen (Chenopodium album), blackberry nightshade (Solanum nigrum), caltrop/cathead (Tribulus terrestris), pigweed/purslane (Portulaca oleracea), African lovegrass (Eragrostis curvula), barnyard grass (Echinochloa spp.), and nutgrass (Cyperus rotundus).
The strategy currently used by many growers to control weeds in cucurbit crops includes a mixture of herbicides, plastic mulch, cultivation, chipping, crop rotation and farm hygiene. Diligence and timing are important factors in a successful approach.
This study identified recent innovative approaches including soil solarisation, biofumigation, cover crops, bioherbicides and biodegradable mulch films. There are also several herbicides registered overseas for use in cucurbit crops that are not currently registered in Australia.
These and other innovations need to be explored fully. The limited range of herbicides registered for use in cucurbit crops restricts growers’ ability to control weeds. Furthermore, plastic mulch may become more expensive in the future due to rising disposal costs, while it may become less acceptable as a crop management method due to environmental impact concerns.
Given these findings, the following areas for future research were identified:
- conducting case studies to improve our understanding of the impact of weeds on cucurbit growers;
- studying the most important weeds in detail, and identifying the best way to control these in cucurbit crops;
- evaluating a range of innovative weed control techniques, either used overseas or by organic growers, to determine their relevance to ‘conventional’ cucurbit producers;
- trialling and, if appropriate, registering additional herbicides to improve the range of products available to growers; and
- making sure that relevant and up to date information on weed control actually reaches cucurbit growers.