Scoping study for sustainable broadleaf weed control in cucurbit crops (VG10048)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Weeds  were  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 Hort Innovation (which was then Horticulture Australia Limited), was a first step in identifying the impact of weeds in cucurbit production, and areas in which weed control may have been improved.

Weeds had a significant impact on cucurbit crop yield and quality, making crop management  problematic. Significant  weeds  included  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 used by many growers to control weeds in cucurbit crops at the time included a mixture  of  herbicides,  plastic  mulch,  cultivation,  chipping,  crop  rotation and farm hygiene. Diligence and timing were important factors in a successful approach.

This  study  identified  innovative  approaches  including  soil  solarisation,  biofumigation, cover crops, bioherbicides and biodegradable mulch films. There were also several herbicides registered overseas for use in cucurbit crops that were not registered in Australia at the time.

These  and  other  innovations  needed  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 have become more expensive in the future due to rising disposal costs, while it may have 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 reached cucurbit growers.