Chilli plants showing fungal damage secondary to sciarid fly infestation.
Sciarid Fly or fungal knat is a serious pest of glass house environments. Adults fly above ground in an erratic fashion, whilst the larval and pupal stages occur below ground. The damage to propagation material is done below the soil by the larvae (maggots). Adults indirectly spread disease through carrying fungal spores on their feet (eg. Pythium). Female adults deposit eggs from 2 days after emergence, live for about a week and can lay up to 200 eggs each. The maggots feed on root hairs or the inside of stem cuttings. The maggot damage creates sites for fungal infection as well as reducing water and nutrient uptake, further weakening the plant. Potato discs are a clever way of monitoring activity and effectiveness of control (discs of potato are placed peeled side down on top of the growing media - larvae feed on this and can be seen underneath or burrowed into discs). Adult flies can be monitored by yellow sticky traps. Conditions favouring sciarid fly include low light levels, high humidity, constantly moist media, media with high levels of organic matter.
Control Measure : to control for sciarid fly, a soil dwelling predatory mite, Hypoaspis, was introduced. These mites are packaged in a pasteurised peat and vermiculite mix for commercial use. They should be released as soon as possible and not stored at temperatures below 10 or above 25 degrees celsius. The material they are shipped in is sprinkled on soil around infected plants.
Aphids were also causing significant damage to chilli plants in the glasshouse.
An initial control measure was to use Eco-Oil, a registered organic insecticide, grown from canola oil and a blend of tea tree and eucalyptus oil. 
It acts by coating and blocking spiracles and suffocating the pest. Protective membranes around pest eggs are also degraded and render them prone to dehydration. It is reported to also have a repellency action on the surface of the leaves, discouraging pests laying their eggs. Eco-Oil can be phytotoxic if overused, causing burning of foliage, particularly with warm weather or if plants are stressed from moisture loss. The oil can block pores on leaves, limiting transpiration. Application rates are 5mL per 1L of water and should be re-applied 3- 5 days later for aphid control.
other control measure : Many had already been parasatised by Aphidius wasps. Female wasps lay its eggs into the body of the aphid. Parasatised aphids are darker in colour compared to normal. Mature wasps cut an escape hole in the back of the aphid and emerge. More of these wasps were introduced to add to existing numbers. They are shipped as aphid mummies and the wasps emerge soon after arrival.
Lacewing larvae, Mallada signata, were also introduced to tackle the aphid problem. Adult lacewings live for about 3-4 weeks and lay up to 600 eggs. Each egg sits on the end of a slender stalk, elevated from the ground to prevent attack by ants. Larvae initially are 1mm but then grow to 8mm before they pupate. They have small spines on their backs upon which they impale their prey, in this case aphids. They camouflage themselves with these dead bodies to appear inconspicuous amongst their prey. They are seen usually by the visible eye as little bits of debris moving around. It is a native lacewing and is most active in warm climates. Adults feed on nectar and pollen, so presence of flowers after release will assist in keeping the lacewings within the target plants. They are shipped as eggs packed in with lucerne chaff along with a small quantity of sterilised moth eggs for food for emergent larvae.
Ref : www.bugsforbugs.com.au
www.goodbugs.org.au
Eco-Oil website
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