Frequently Asked Questions

Pests and diseases

How can I get rid of moles?

Moles are blind, but have an extremely astute sense of hearing and smell, so excessive movement or strange smells can scare them away. If they burrow underground, it will be difficult for you to capture them.

If you have a mole infestation then you have to make one of two decisions. You either kill & destroy them or catch them humanely and take them FAR away. Either method is difficult for beginners, but experienced mole catchers can do the job very efficiently, quite effectively and successfully.

THE FATAL & PERMANENT WAYS

1. There are specially designed mole traps that go into a mole run (the tunnel they use), usually accessed via a big mole-hill. You dig down a little and if you discover a run that goes both ways then there's a good chance you'll catch one - you don't need bait but you rely on the mole to bump into it thereby triggering the mechanism that clamps around it's body. Don't try rat or mouse traps you'll have no success at all (a method cooked up by someone who does not know much about moles - or probably have never seen one). With their incredible sense of smell a mole can easily be spooked and won't go near your trap. Old mole catchers would go to great lengths to hide the smell that gets transferred from your hands on to the trap. They never used perfumed soap, kept their traps in manure and some even rubbed manure on their hands to disguise the human odour!

2. Smoke bombs. These are not available in all countries, depending on the permitted use of certain poisons in those countries. This is a VERY effective method. Smoke 'bombs' will kill the moles in their tunnels. You simply put a smoke bomb at intervals into the tunnels & light them. The poisoned smoke permeates through the tunnels and "gases" the moles that use them.

3. manual hunting. If you quietly sit in the area where moles are active (they tend to feed during the early morning, around noon and in the evening). This requires a lot of patience and quite a degree of skill. Carefully scan for any movement of the grass or soil, that indicates a mole is active under ground, their tunnels often come quite close to the surface & sometimes form a long mound where the displaced soil stands proud of the surrounding area. You can use two spades or a spade/ shovel & hammer (gruesome - but this is reality). When you observe a mole at work you VERY quietly approach the spot from behind and slam the spade down into the ground blocking the mole from reversing back down the tunnel it's making, thereby blocking it's escape. You then either do the same with the other shovel in front of it. Dig it out and despatch it. If you're using one spade & a hammer you know what to do with the hammer!

4. Flood the tunnels using a hosepipe. The idea is to flood the tunnels forcing the moles to the surface or cause them to drown underground. This is a very ineffective and unreliable way of doing it.

5. Shoot them. It sounds crazy, but this is the favoured method with many farmers. It can also be very effective once you develop the skill. Again you wait to see the activity of a mole and this time instead of using a shovel you use a 12 bore shotgun firing into the ground in the immediate vicinity of the mole. Often the shock will kill them and not the lead shot.

6. An older method was to contaminate worms with strychnine by immersing them in the poison and then distributing the worms in the tunnels. This method has died out because strychnine is not available and possibly more mole catchers have been killed by the poison in the past than moles. A single grain of strychnine is fatal to both moles & humans!

THE HUMANE WAYS

A mole is difficult to trap alive. It can be done, but with very limited success. With it's enhanced senses of detection it's not easy to get it into a box!

Probably the most effective way is to use the "spade" method described above, but instead of killing the animal, you drive your spade into the ground behind it and then in one movement toss it out of the ground and into the air. Suffice to say it takes an AWFUL amount of patience & dexterity!

When it comes to deterrents you can either use very strong smelling compounds (like soap mixtures or disinfectants) to contaminate the area by introducing these smells into the tunnels. Mediocre results will be experienced and the moles are still free to roam the area.

Put sprigs of holly in the tunnels. The idea being that it forms a barrier because of the mole's sensitive nose. Again limited in it's efficiency. Some say that if a mole has it's nose pierced then it will bleed to death. This is highly contentious and unproven.

What's causing the black marks that are developing on my Runner Bean pods?

Your beans are likely to be suffering from the disease bean anthracnose, which affects both runner and dwarf French beans.

Brown stripes develop on the stems, reddening on the underside of the leaf veins. This is often followed by the leaves withering and dying. Rounded, reddish spots then develop on the pods and soon spread to the developing beans.

Affected plants should be destroyed and healthy ones could be sprayed with a suitable fungicide (copper based types are approved by the Soil Association so are OK for organic growers) to protect against infection. Next year make sure you grow your beans in a different part of the garden and spray to protect them if necessary.

This is one of the problems experienced when the same crop is grown in the same soil for many years. Hence the importance of crop rotation.

What’s the cause of ringed spots on leaves?

Large spots of concentric rings on brassica leaves, particularly older ones, indicates ring spot, caused by a fungus (Mycosphaerella brassicicola). It causes circular brown-purple patches up to 2.5cm wide on leaves and stems. The patch is sprinkled with tiny black dots arranged in concentric rings. These are the source of the spores of the disease. Eventually, the whole leaf yellows, withers and is shed. This disease is favoured by mild, wet conditions, and although widespread, does its worst damage in the south-west. Brussels sprout buttons are severely affected.

Burn or bin badly affected plants.

Avoid excessive manuring as lush plants are more susceptible. If plants are too lush or the site is very fertile, add 30g a sq m of sulphate of potash to promote stronger, more disease-resistant growth. Don’t grow cabbages in the same spot each year as the disease can persist. ‘Roscoff’-type cauliflowers have some resistance, but are tender so can only be grown near the coast or on protected sites. Destroy badly affected plants and rotate your crops. Seedlings should not be raised in infected soil so it may be best to raise your plants in pots or cell trays.

What is responsible for the white dusty covering on leaves?

Dusty, whitish coverings of leaves and stems is a sign of crucifer powdery mildew (Erysiphe cruciferarum). This spreads by airborne spores. Swedes and Brussel sprouts are the usual victims in gardens, but other plants can be attacked. Sprouts develop black spots that ruin their appearance and they need extra trimming before eating. In severe attacks the leaves turn yellow and fall. This disease is worst in the south-east.

Hot, dry seasons are favoured by powdery mildew. It especially affects plants on light or sandy soil. This can be helped by extra watering. Wider spacing of plants also reduces the disease’s severity.

Many brassica varieties are said to be resistant. In practice, such varieties still may be affected. Late-sown crops are often less affected. Late sowing of turnips and swedes (in June) may reduce disease. Excess nitrogen makes plants more susceptible. Powdery mildew survives the winter on old plant material. Burn, bury or completely compost old plants to prevent carrying over the disease into the new year.


What causes brassica leaves to go mouldy?

Yellow spots on leaves and corresponding white, fluffy patches on the leaf undersides, are signs of downy mildew (Peronospora parasitica). You don’t usually see downy mildew outdoors, except in warm, humid areas near the sea, or in very sheltered, low-lying gardens. Mild, wet autumn weather is the most likely period for attacks. Look out for yellow-brown patches between the veins on the upper leaf surfaces, with white, downy patches beneath the leaves showing up only in wet weather. By then, the plants are big enough not to be seriously affected, although leaves may be lost and sometimes edible parts like cauliflower curds are damaged. Yield loss can also be caused by black spots and streaks inside produce, although other diseases may also cause this. Downy mildew damage can open the way for other diseases. Plants in cloches, frames and greenhouses are much more likely to be infected. In spring and autumn, seedlings are the usual victims, when the weather is mild and humid and the plants are close together. Wallflower plants that are raised indoors are especially at risk in early autumn; they can be stunted or even killed by these attacks.

Mature plants in prone sites can be protected by spraying with sprays containing mancozeb every 14 days. Keeping down weeds and avoiding overcrowding will also help prevent attacks. In cloches, frames and greenhouses, thin out the plants, spray every two weeks and, ventilate as much as you can.

Downy mildew is soil-borne, so growing brassicas in a different spot each year will help prevent the disease. It gets into the plant through the roots and spreads to the leaves, where the downy patches form. Then it spreads from plant to plant on the breeze. Prevent spread, including to the soil, by pulling up and binning or burning affected plants. Ensuring the soil has sufficient potassium and magnesium is said to help plants resist these attacks. Some varieties, such as the calabrese ‘Marathon’ are said to be tolerant of downy mildew.

What causes white spots?

If small, white, smooth, shiny patches like scales appear beneath the leaves, white blister (Albugo candida) is probably to blame. It starts off as green blisters, which then form white warts, eventually turning powdery. It occasionally distorts the heads of cauliflowers, cabbages and broccoli, and disfigures Brussels sprouts. It may attack stems and flowers as well. Seedlings can be affected. White blister looks serious but seldom reduces either growth or yield.

It is worst where air flow is poor and the atmosphere humid. It spreads by rain splash, wind and insects carrying its spores from plant to plant. Sheltered gardens are likely to be more affected than open allotments. Warm, wet autumn weather is the most likely period for attacks. Remove the worst-affected plants by burning, burying or binning. Keep plants spaced out, especially in seedbeds. Resistant spores can remain in the soil, so grow cabbage-family plants in a different spot each year.

There is no completely effective spray available to gardeners, though sprays containing mancozeb may give some control. Some Brussels sprout varieties are thought to be partly resistant.

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