How to kill your pests
(Otherwise known as Murder in the garden, and definitely a last resort...concentrate on growing things well, and you won't need to go a killing)
Very Simple Pest Control
In most cases you don't need to know what the pest is. You can control if if you just watch what it's doing.
*Little things that suck sap so your plant turns yellow or looks sand blasted or has a tracery of fine lines over the leaves or little beasties that cluster on leaves or new shoots: (aphids, mites, thrips, bean fly, scale): hose aphids off or squash them between your fingers or use an old toothbrush to scrape off tougher pests. If you need to spray, use an oil spray according to directions on the bottle. This suffocates pests.
*Things that go chomp, chomp, chomp and take great chunks out of your leaves (caterpillars, smaller beetles): mix one cup derris dust (from the Garden Centre) to ten cups water and spray (buy a pump sprayer at the Garden Centre). Derris is a stomach poison so any insect that eats the leaves it's been sprayed on dies. Repeat every few days.
*Great horrible bugs and beetles: Shake the tree and stamp on the beetles. Spray the leaves with a derris and water spray - don't spray the beetles, they won't be affected. They need to eat the poisoned leaves.
Does your plant have wet feet? (The roots will probably rot.)
Is your plant in a hot exposed place? (Small leaves, drooping yellow leaves or brown blotches may mean it's getting sunstroke.)
Is it choked by weeds or grass? (It may yellow and die of mildew and starvation.)
Is it getting enough light? (If the poor thing strains towards the sunlight, move it or prune around it.)
Does the soil around it feel like concrete? (Mulch and water.)
Remember: Pots dry out and heat up faster than gardens, and need more frequent feeding and watering.
Is your plant hungry?
SYMPTOMS: foliage yellows, either young or old leaves or between veins; plants are stunted,crops are small and may drop off before maturityCORRECTION: the best food for plants is the residues of whatever has lived before- plant and animal matter. Compost and mulch should be all the feeding plants need. .If in doubt give plants a daily dose of liquid foliar fertiliser for a couple of weeks. If this improves your planst keep doing it, once a wek or fortnight (depending on how strongly your plants are growing) while you correct your feeding program.
What yellow leaves may tell you
If the oldest leaves are yellowing and not the young ones you have a nitrogen deficency. If the young leaves are yellow you may have a phosphorous deficency.If all leaves seem to be yellowing evenly check that the plant isn't waterlogged or starved of water - plants need water to transfer their nutrients. Rock the plant to see if it seems loose - this would mean root rot. Cold weather will cause leaves to turn yellow. So will herbicide drift. Check the base of the plant for collar rot or injury from a motor mower.
This looks disgusting, but it works very good; on shield bugs especially, plus of course aphids, bean fly et al, and VERY good on tiny caterpillars that are too small or green to see and squash.
mix 1 cup boiling water with 1 cup white flour. Mix well. Add cold water till it's thin and sprayable. Strain well. Spray on thickly on top and under the leaves. Repeat after five minutes if you think it;s not quite thick enough. Wash sprayer well or you'll have to soak it for ages.