Pacific Pests, Pathogens and Weeds

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Summary

• Worldwide distribution. In Australia, Cook Islands, New Zealand, Papua New Guinea. Many important crops and weeds are hosts.
• Major virus disease of tomato (TSWV). Plants stunted; leaves drooping, bronzed with dark spots and streaks (also on petioles and stems). Fruits with distortions, yellow, black or ring spots, or mosaic patterns. Symptoms variable (age, host, temperature).
• Spread: thrips. TSWV survives in volunteer plants and weeds.
• Biosecurity: see Plant Health Australia contingency plans for thrips transmitted diseases: (https://www.planthealthaustralia.com.au/wp-content/uploads/2013/03/Thrips-transmitted-viruses-CP-2011.pdf).
• Biocontrol: commercial strains of Beauveria fungus.
• Cultural control: use certified seed; check seedlings for symptoms; weed around nurseries and crops (aim for 10m weed-free area). (Note, grasses are poor hosts of TSWV.) Avoid overlapping or consecutive tomato crops, use a rotation with non-hosts; avoid excessive nitrogen; monitor with sticky traps; rogue plants with symptoms; collect and destroy debris after harvest.
• Chemical control: use soap, white or horticultural oils; in Australia, abamectin, spirotetramat, spinosad, spinetoram, Beauveria bassiana, are registered. Avoid broad-spectrum insecticides.