Insects as virus vectors

In field crops, plant viruses and related diseases can be transmitted by a number of insects. Aphids are considered to be the most important, but whiteflies, leafhoppers, thrips and beetles may also be virus vectors.

The most common field crop viruses and their vectors include:

Pest

Virus

Crop

Green peach aphid Beet western yellows virus
Cauliflower mosaic virus
Turnip mosaic virus
Canola
Cabbage aphid Beet western yellows virus
Cauliflower mosaic virus
Turnip mosaic virus
Canola, Pulses
Cowpea aphid Beet western yellows virus Canola, Pulses
Cucumber mosaic virus Pulses
Turnip aphid Cauliflower mosaic virus Canola
Turnip mosaic virus
Cucumber mosaic virus Pulses
Green peach aphid Bean yellow mosaic virus Lupins, soybean, peanuts, faba beans
Thrips Tobacco Streak Virus Sunflower, mungbeans
Western flower trips Tobacco spotted wilt virus (TSWV) Peanuts
Maize leafhopper Wallaby ear mycoplasma Maize

Early colonisation by virus-infected aphids can result in major yield losses. Yield losses of up to 50 per cent from the combination of BWYV and green peach aphid have been recorded in WA with infections very early in the growth of the crop.

How to manage virus transmitting aphids

  • Insecticides are not the preferred solution. Vectors for non-persistent (and partly semi-persistent) viruses need relatively short inoculation times – much shorter than the time needed for insecticides to kill. Insecticides can induce restlessness in insects, which may result in more inoculation attempts.
  • Use resistant varieties
  • Reduce virus sources
    • use virus free seed
    • remove infection sources e.g. weeds, volunteer crops
  • Interfere with vector landing on crops
  • Trap crops may be preferred feeding sites for vectors – preventing infection of the main crop.
  • Mineral oils – aphids are averse to mineral oils
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