Leafy vegetables – an overview:

This page provides an overview of the key pests and diseases of leafy vegetables in Australia. The related tools provided at the end of the page can be used by growers and crop consultants to accurately identify the range of pests and diseases encountered in leafy vegetables, particularly lettuce. They include photographs and detailed information about specific pests. For unknown pests, it is important to have an expert identify them so that they can be managed appropriately.

Leafy vegetables include lettuce, celery, silverbeet, spinach, rocket and parsley. Lettuce is grown hydroponically, as well as in the field. A range of pests can cause problems in leafy vegetables, including slugs and snails.

Key pests of leafy vegetables:

Crop

Insect pests

Diseases
Lettuce Aphids (including Currant lettuce aphid); Thrips (including Western flower thrips); Heliothis (Helicoverpa); Looper caterpillar; Cluster caterpillar; Rutherglen bug; Whiteflies; Wireworm; False wireworm; Vegetable weevil; Cutworm; Lucerne leafroller; Leafhoppers; Fungus gnats. Downy mildew; Bacterial leaf spot; Grey mould; Sclerotinia rot or Lettuce Drop; Damping-off (Pythium, Rhizoctonia, Fusarium, Aphanomyces or Phytophthora Root and Stem Rots); Bacterial Rots; Varnish Spot; Corky Root; Septoria Leaf Spot; Anthracnose; Tomato Spotted Wilt Virus (TSWV); Mosaic and Necrotic Yellows.
 Celery Thrips (onion, tomato, and western flower thrips); Heliothis (Helicoverpa); Cutworm; Aphids; Two-spotted mite; Rutherglen bug; Leafhoppers. Celery mosaic virus; Tomato spotted wilt virus; Cucumber mosaic virus; Bacterial leaf spot; Fusarium yellows; Late blight; Downy mildew; Powdery mildew; Grey mould.
Silverbeet Western flower thrips; Beet webworm; Weevils; Mites (two-spotted mites); Green vegetable bug; Heliothis caterpillar; Cutworm; Looper caterpillar. Cercospora leaf spot; Root rots; Root-knot nematodes; Leaf and Stem Rot.
 Spinach (English) Aphids; Caterpillars; Leafhoppers; Thrips. Downy mildew; Leaf spots; Root rot; Wilt; Mosaic virus; Nematodes.
 Parsley Thrips; Cutworms; Wireworms; Looper caterpillars. Alternaria leaf blight; Bacterial leaf spot; Botrytis blight (Grey mould); Downy mildew; Powdery mildew; Fusarium root rot; Rhizoctonia crown and collar rot; Root rot; Sclerotinia rot; Septoria leaf spot; Root-knot nematodes; Viral diseases (Apium virus Y; Carrot red leaf virus).
 Rocket Cabbage white Butterfly; Green caterpillar. Leaf spot; Clubroot.

Pest management:

Integrated pest management (IPM) is used to control pests without relying on pesticides alone. With an IPM approach, pesticides provide support for other control measures such as weed management, variety selection, crop rotations, biological control, and protection of beneficial insects.

  • Identify key pests and understand their lifecycles, including what naturally eats/kills them (natural enemies and climatic conditions).
  • Prevent pests from being in your crop or increasing in numbers to the point of causing economic damage.
  • Monitor crops for pests and numbers. This will allow you to target the most vulnerable life stage of a pest and discover when an insecticide is most effective. Monitoring will also tell you if an insecticide, which can sometimes fail because of weather conditions, spray equipment, or the expiry date of the chemical, has worked. Pheromone traps help identify which of the two heliothis species is dominant. Yellow sticky traps help monitor thrips and control their numbers. Prediction models should be used when insect pests or diseases are most likely to be present.
  • Beneficials that can assist in pest management in leafy crops include – Ladybird beetles; Lacewings; Hover flies; Predatory wasps; Spiders; Parasitoids (e.g. Trichogramma spp.); Aphid parasitoids; Non-insect beneficial organisms (e.g. Heliothis Nuclear Polyhedrosis Virus and Bacillus thuringiensis)
  • Use beneficials – the most common types of beneficial insects found in celery crops include ladybirds; brown lacewings which feed on aphids, small caterpillars, and moth eggs; damsel bugs which feed on caterpillars and other soft bodied insects; and Aphidius – a small wasp that eats aphids.
  • Control weeds as they can harbour insect pests and diseases.
  • Control the pest when numbers are causing economic damage. This includes mechanical methods (chipping weeds or diseased plants); biological methods (introduce a beneficial insect or use a biological spray); or chemical methods (pesticides).
  • Evaluate immediate effectiveness of direct controls and overall success of the pest management program. Identify potential areas for improvement and develop a plan for future plantings. Growers need to assess the information collected through monitoring, along with other factors such as the age of the crop or the growth stage of the plant, weather conditions, age of the pest, withholding periods and crop value.

Source of information and related tools: