Ian . I recently found a large infestation of insects in my greenhouse. They are dark and crusty and roll up into a circle when disturbed. What are they and do they harm plants? Thanks R.G. Buncrana
Reply: The creatures you mention are members of the millipede family. Millipedes have between 30 – 400 legs and have a hard-shelled, round, segmented body and short antennae. They have 2 pairs of legs per body segment. Many have an offensive odour. These pests move slowly but they are very determined. To give you an idea what to look out for in the soil the eggs are small and white. These eggs are laid in clusters of 20 to 100 in the soil and hatch in about 3 weeks. Females lay as many as 300 eggs in the summer. As they get older the millipedes moult their skin and grow larger. You have found the pests in the greenhouse because the adults over winter in the ground. As you have mentioned they curl up when disturbed, this is to protect themselves from predators.
Plants attacked
Millipedes like tomatoes and strawberries. They also like cucumbers, squash, melons, beans, corn, peas, and root crops such as beets, carrots, parsnips, turnips and potatoes. They like overripe fruit too. They live in moist soil and congregate around the plants in soil that is rich in organic content. Since they don't have a waxy coating they dry out easily and die. So compost piles, leaves and other plant debris are favourite wet places to hide under during the day. Millipedes feed on the foliage, stems and roots of healthy plants. They can also damage seedlings.
Prevention
There are some precautions you can take to keep the pest down. Cleaning up plant debris (especially decaying material) and eliminating wet areas may help control these creatures. This could still be unsuccessful though. I had a lot of millipedes in my tunnel one year and even though I thought I kept a clean house they still thrived. If you are growing fruit in the greenhouse, try to keep it off the ground and pick when it ripens. I have tried the same traps that I use for slugs. Beer traps and upturned pots with grass in, but these methods only catch a few. The other method would be to wet the soil thoroughly and cover with black plastic. Get up early the following morning and you will find the pests on the surface of the soil. Scoop them up and dispose of them as you will! Someone suggested putting dilute Jeyes fluid into the soil. I’ll let you know how the experiment works out.
PEST FREE GARDENS
Millipedes are not the only pests to be found in gardens. A healthy plant is a pest free plant so here are a few tips for keeping a pest free garden.
1 Choose plants that look after themselves
Don't create a plant protection problem by trying to grow unsuitable plants. If they are growing in the right conditions most established plants - and especially natives - will shrug off all but the most severe pest attacks.
If you have persistent problems with particular plants, try moving them somewhere else. If you can't find anywhere suitable, give up the unequal struggle and grow something different - they are trying to tell you that they don't belong in your garden at all!
2 Give new plants a fighting chance
Beware sowing or planting seedlings too early, especially on a cold, heavy soil. When plants have to cope with soil or weather that is too cold for them, they struggle to get going and are a sitting target for pests. You can use cloches or fleece to warm the soil first and to protect plants in the critical first week or so. You can also sow indoors in pots or a container and plant out when the seedlings are big enough to survive a few nibbles. Remember to keep back a few spares to replace the plants you do lose - it usually involves no more cost and little extra effort.
3 Nip problems in the bud
Get used to looking at your plants closely and often. If you have not done it before, it will open up a new world of tiny creatures engaged in a continual battle for survival. It will also enable you to detect the most destructive pests in the early stages, when a few quick squeezes between finger and thumb may snuff out the problem (millipedes sound very crispy!). You will also be able to see whether or not natures own defenders (for example ladybirds) are winning before you bring in the reinforcements!
Horticultural.
Reply: The creatures you mention are members of the millipede family. Millipedes have between 30 – 400 legs and have a hard-shelled, round, segmented body and short antennae. They have 2 pairs of legs per body segment. Many have an offensive odour. These pests move slowly but they are very determined. To give you an idea what to look out for in the soil the eggs are small and white. These eggs are laid in clusters of 20 to 100 in the soil and hatch in about 3 weeks. Females lay as many as 300 eggs in the summer. As they get older the millipedes moult their skin and grow larger. You have found the pests in the greenhouse because the adults over winter in the ground. As you have mentioned they curl up when disturbed, this is to protect themselves from predators.
Plants attacked
Millipedes like tomatoes and strawberries. They also like cucumbers, squash, melons, beans, corn, peas, and root crops such as beets, carrots, parsnips, turnips and potatoes. They like overripe fruit too. They live in moist soil and congregate around the plants in soil that is rich in organic content. Since they don't have a waxy coating they dry out easily and die. So compost piles, leaves and other plant debris are favourite wet places to hide under during the day. Millipedes feed on the foliage, stems and roots of healthy plants. They can also damage seedlings.
Prevention
There are some precautions you can take to keep the pest down. Cleaning up plant debris (especially decaying material) and eliminating wet areas may help control these creatures. This could still be unsuccessful though. I had a lot of millipedes in my tunnel one year and even though I thought I kept a clean house they still thrived. If you are growing fruit in the greenhouse, try to keep it off the ground and pick when it ripens. I have tried the same traps that I use for slugs. Beer traps and upturned pots with grass in, but these methods only catch a few. The other method would be to wet the soil thoroughly and cover with black plastic. Get up early the following morning and you will find the pests on the surface of the soil. Scoop them up and dispose of them as you will! Someone suggested putting dilute Jeyes fluid into the soil. I’ll let you know how the experiment works out.
PEST FREE GARDENS
Millipedes are not the only pests to be found in gardens. A healthy plant is a pest free plant so here are a few tips for keeping a pest free garden.
1 Choose plants that look after themselves
Don't create a plant protection problem by trying to grow unsuitable plants. If they are growing in the right conditions most established plants - and especially natives - will shrug off all but the most severe pest attacks.
If you have persistent problems with particular plants, try moving them somewhere else. If you can't find anywhere suitable, give up the unequal struggle and grow something different - they are trying to tell you that they don't belong in your garden at all!
2 Give new plants a fighting chance
Beware sowing or planting seedlings too early, especially on a cold, heavy soil. When plants have to cope with soil or weather that is too cold for them, they struggle to get going and are a sitting target for pests. You can use cloches or fleece to warm the soil first and to protect plants in the critical first week or so. You can also sow indoors in pots or a container and plant out when the seedlings are big enough to survive a few nibbles. Remember to keep back a few spares to replace the plants you do lose - it usually involves no more cost and little extra effort.
3 Nip problems in the bud
Get used to looking at your plants closely and often. If you have not done it before, it will open up a new world of tiny creatures engaged in a continual battle for survival. It will also enable you to detect the most destructive pests in the early stages, when a few quick squeezes between finger and thumb may snuff out the problem (millipedes sound very crispy!). You will also be able to see whether or not natures own defenders (for example ladybirds) are winning before you bring in the reinforcements!
Horticultural.
No comments:
Post a Comment