Today: Peeking at pests.
I’m sure in the grand design, everything has a purpose but my research has failed to pinpoint the one served by Aphids and Glasshouse Whitefly. They are from different families and so, as with all villainous characters, have different enemies. But to the good guys (that us tomato growers) their behaviour looks the same.
Essentially:
- Suck plant sap
- Excrete honeydew; sticky stuff which attracts black sooty mould
- Grow out of and discard outer skins; leave behind as more unwanted debris on the plant
Sucking sap from the plant is a vampire like activity which weakens it and affects its growth.
In addition aphids are a vector for viruses. If they suck on plant tissue which is infected with a virus and then move on to healthy tissue, they pass on the virus.
Chemical control
- Not an option on edible crops plants. The exception being Thiacloprid, a systemic insecticide
- Organic insecticides include fatty acid/insecticidal soaps, some plant oils used as sprays and Pyrethrum, a flower extract.
Biological control
- Aphids
Aphidius species. Parasitic wasp whose larvae deveop inside the aphids body
Aphidolete aphidimyza .Predatory midge whose larvae eat aphids - Glasshouse Whitefly
Encarsia Formosa. Parasitic wasp whose eggs hatch inside and feed off the Whitefly nymphs
Cultural control
- Sticky yellow paper traps; hung above the plants to bring an end to all that merry making. Having traps in place can also serve as an early warning indicator. When they started getting covered, time to call the biological boys
- Companion planting of French marigolds and basil is thought to deter Whitefly
