Pacific Pests, Pathogens and Weeds

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Summary

• Worldwide. Asia, Africa (restricted), North and South America, Europe, Oceania. In Australia.
• A serious disease causing yield and quality losses in cucumber and watermelon. Also in bitter and bottle gourds, melon, and wild species in amaranth, cucumber, potato and other families.
• Symptoms:
  • cucumber – leaf crumpling, green mottling and mosaic patterns, irregular light green spots or streaks on fruits; plants may collapse;
  • watermelon - stunting, mottling and mosaic patterns on leaves, rots on stems and fruit stalks, fruits with internal discolouring or rots. Plants may die early;
  • melon - mottling and mosaics, deformities and mottling on fruit;
  • pumpkin - no symptoms or mottling/mosaics on leaves or fruits;
  • squash/zucchini - no mottling/mosaics; internal discolouring or rots in fruits.
• Spread is in seed and soil. Also handling, grafting, leaf-to-leaf contact, bees, manures, hydroponics/irrigation, tools, machinery, clothing, root-to-root contact. Survival in seed, crop debris and soil.
• Cultural control: certified seed; biosecurity plan for farm; disinfect pots, trays, machinery (1% sodium hypochlorite); use disposable gloves if grafting; check each seedling in the nursery; weed; monitor; collect crop remains after harvest, stakes, plastic mulch, and burn; use 2-year rotation if plants infected; resistant varieties.
• Chemical control: not a method recommended.