Karen is new to organic gardening and is wants to know what to do about the green vegetable bugs that are attacking her tomatoes.
The green vegetable bug is a sap-sucking pest. They use weeds as hosts and attack vegetable plants that are stressed in some way. Of the chemical sprays required to kill these bugs, one will poison any birds that eat the bugs, and the other is deadly to bees and other beneficial insects. It can also metabolise in humans to a more toxic chemical, and is currently under review.
Chooks show no interest in eating these bugs. The best way to get rid of these organically is to put some methylated spirits into a soup tin or similar container. Put on gloves to protect your hands from any smelly juice they excrete and use a stick to knock them into the tin. Then get rid of weeds and plants that have finished bearing to prevent these pests continuing to breed.
To prevent further attacks (and this is the most important part of the treatment) have a look at why your tomato plants are stressed, and correct the problem. Some gardeners find it difficult to understand that pest and disease attack are only symptoms of unsuitable conditions for a particular species, but it is true. I noticed yesterday, that similar bugs are attacking some silver beet plants we have. We decided after picking the first of this silver beet that we did not like this variety as much as ‘Fordhook’ and decided to just feed the plants to the chooks, a plant or two at a time. Consequently, the silver beet did not receive the same attention as the other vegetables and, before long, these bugs moved in. The bugs are not attacking other vegetables that are receiving normal care.
When pests attack plants, the answer is always in the soil. It may be too dry or poorly drained. If water is in short supply in your area, hill up your tomatoes about 5 cm at a time. They will produce more roots along the stem and allow them to access water more efficiently. Tomato plants need a deep watering (under mulch) several times a week in dry weather, rather than a light daily watering.
Or, the plants may be short of the nutrients they require to produce pest-deterring pheromones. If you have skimped on fertiliser, after a thorough watering, give each plant a light feed of complete poultry-based fertiliser and a drink of seaweed extract tea.
Or, the soil may be too acid or alkaline for the plants and the nutrients they require can be locked out and unavailable to the plants. This can be difficult to determine without testing, except that, with tomatoes symptoms of phosphorus deficiency (purple colouring under leaves and slow growth) are a clue that soil is too acid or alkaline if you have applied adequate complete fertiliser. If soil is too alkaline, put some well-rotted horse or cow manure under the mulch around the plants. If soil is too acid, water in some dolomite or lime around the base of each plant. See Changing soil pH.