What's your plant problem?
Before you look for treatments, you really need to find what the problem is. This page suggests a logical approach to hunting down the enemy...
It may be worth starting right at the beginning - by examining the symptoms. If your plants look sickly it could be caused by:
- 1. Shortage of food or water
- 2. Disease (bacteria or virus attack)
- 3. Attack by mould or fungus
- 4 Larger birds or mammals eating the plants
- 5. Something eating the roots
- 6. Something eating the stem, leaves or flowers
Biological Controls will only help you with problems 5 and 6. So you need to actively look for, and be able to identify, a pest attack before you just assume that a sickly plant needs treatment.
Visible damage to stem, leaves and flowers
If the visible part of the plants are attacked then it is often possible to identify your pest by looking carefully at the damage...
|Damage to leaves, stems and bark. Leaves bitten with large bites.Damage over a number of plants||Attack by deer, rabbits, pigeons and large birds||
|bite-shaped damage round the edges of shrub leaves, making a scalloped pattern||Symptoms of an insect with large strong cutting mouth parts which is chewing up the leaves from the edges inwards||
Vine Weevil Adults
|irregular holes in the middle of leaves, and at edges. Often a tell-tale slime trail||Symptoms of a creature that nibbles away at leaves from above||Slugs and Snails|
|Tiny holes in leaves like gunshot typically found on herbs and salad brassicas in spring and summer.||caused by tiny flying and jumping insects which land on leaves and bore holes right through.||Flea Beetle|
|irregular holes in the middle of leaves, with some at edges. Leaves between main ribs slowly and progressively eaten until skeleton remains||Symptoms of a creature that consumes as it crawls, and has weaker mouth parts, and so keeps to the tender part of leaves||Caterpillars|
|Patches of dead cells in the centre of leaves or on edge||Symptoms of a creature that consumes as it crawls, and has weaker mouth parts, and so keeps to the tender part of leaves||Leaf miner (adult shown)|
|mottled pattern on leaves (in worst cases there is fine webbing between leaves). The damaged areas may be cream, white, or rust coloured. Found in hot dry periods.||caused by tiny mites which feed on soft new growth and leave strips of leaf cells dying within the leaf||Spider mites|
|Tiny patches of damage on leaves - stripes and blotches on flowers||caused by tiny crawling larvae which suck out jucies from leaves||Thrips adults|
|Distorted leaf outlines - typically found on capsicums||Caused by chewing the young tissue - When leaves or buds expand they may become distorted or torn, forming holes in the tissue||Thrips larvae|
|Yellowing leaves followed by black mold||Caused by larvae sucking the young tissue which makes the leaves die slowly - the black sooty mould grow on the honeydew, a sticky substance exuded as the insects feed||
Many flying insects have young which feed underground. Whether or not you can find root damage, you should be looking for any "grubs" that could be fattening themselves on the underground parts of your plant. Even if they are dormant because they are hibernating, they will wake up in spring and start feeding. Not all things that look like "grubs" are actually bad news - some of them eat other creatures rather than eating plant material. And some creatures are just sheltering underground in one of the stages of their life cycle. The four that you need to look out for are: vine weevil, sciarid, chafer bug and leatherjacket.
|Visible Root damage||It's worth gently easing pots plants out of their pot to look at the root ball. Healthy roots are fine, strong and supple, and cling to the soil. If you are looking for root damage in your pot plants then look for dry and brittle roots, with a lighter colour..||Vine Weevil grubs|
|Damage in root vegetables||Carrot Root Fly is a prime example where tiny, near invisible larvae eat away at your vegetable roots underground. Note the dark tunnels. Several kinds of fly have young (larvae) which feed on roots, but some are particularily adapted to munch at vegetables and bulbs. Suspect Carrot Root Fly, Cabbage Root Fly, Onion Fly, cutworms....for a multi-pest approach we offer the Nemasys "Grow Your Own" pack with a mix of nematodes.|