Root lice: how to recognize and fight mealybugs

Mealybugs are usually easy to spot because they attach themselves to the leaves of the plant and can be seen there with the naked eye. But there are also mealybugs that attach themselves to the roots of plants underground, these are known as root lice and are much harder to spot. To ensure that the plants are not damaged, they must be observed regularly.

Root lice - definition

Mealybugs, aphids or scale insects, which also belong to the same family as the root lice belong are recognized quickly, since these are on the leaves and stems of the plants settle. But root lice are plant lice that live underground and are therefore not easily seen. The root lice surround themselves with white or off-white waxy secretions and suck on the roots of the infested plant. Root lice live in large colonies and therefore there is always a heavy infestation. Root lice look like this:

• small animals, two to three millimeters in size
• present in abundance at the root of the plant
• Excretions on roots, root collars and soil
• white waxy powder

Another indication of an infestation is a large number of red ants near the plants. Small mounds of earth next to the plants are also formed by the root aphids.

damage picture

Above all, plants that are already weakened are attacked by the underground mealybugs. This includes plants that show signs of deficiency, have already rotted due to waterlogging, or the soil around the roots is heavily compacted. The damage to infested plants is as follows:

• wither in growth
• wilt even though they are sufficiently moist
• die off
• this can result in large defects in plant cultures
• root aphid infestation is associated with ant infestation
• this is due to the honeydew excreted by the lice

In the case of useful plants, the harvest is less or not at all. Lettuce plants, for example, wilt from below and turn yellow. Affected berry plants have a lower yield, but the plant itself is hardly affected. Young bushes stop growing. Ornamental and indoor plants can suffer considerable damage and die off altogether.

Happen

Almost all ornamental and vegetable plants can be attacked by root aphids. But the pests have a preference for spurge and succulent plants. But flower bulbs are not spared either, and so tulips or daffodils can also infest them, as can many other bulbous plants. Since there are different species of root aphid that can even be host specific, like the lettuce root aphid, to name an example, no plant is safe from an infestation. The root aphid is very common, especially in the following vegetable crops:

• endive, lettuce or chicory
• carrots, celery or parsley
• gooseberries and currants
• indoor plants
• Dieffenbachia, rubber tree, palm trees, cacti
• Balcony plants such as geraniums or carnations

Many root aphid species overwinter in the plant debris on the ground, so it is important that all debris is completely removed after harvest. In this way, a renewed infestation in the following year can be contained or avoided.

Prevent

Preventing an infestation is better than fighting an infestation. Because precisely when the soil conditions are unfavorable for plants of all kinds, root aphid infestation occurs. The pests prefer compacted or dry soil, so it should always be kept loose and watered sufficiently. Waterlogging should also be avoided here, however, because the pests also like to attack these weakened plants. Other preventive measures are as follows:

• regular crop rotation in vegetable cultivation
• Create mixed culture
• Tomatoes, onions and leeks go well together
• keep the pests away with their smells
• choose resistant varieties from the trade for lettuce
• create drainage to prevent waterlogging in the bed or tub
• Lay out insect protection nets (ground flea net) over crops in the garden

Fight

Once a plant or even an entire vegetable patch has been infested by root aphids, it becomes difficult to combat them. A distinction should also be made here between perennial and annual plants when combating them. In the case of annual, infested plants, it is often not worth the effort to save them. The progress of the infestation is also important here, how to proceed:

• Expose root area
• Water regularly with tansy or nettle broth
• dig up infested plants cultivated in pots
• Rinse the roots and completely remove the lice
• then place in a water bath for several hours
• plant in fresh soil
• Clean pots thoroughly beforehand
• use natural enemies in the garden bed
• Add commercially available neem worms to the irrigation water

As soon as a bed with carrots or lettuce plants is very badly affected, it makes more sense to destroy the plants completely and remove and clean the soil. The infested plants and the remains of them should never be put in the compost but should be disposed of with household waste. Because the root aphids can hibernate on the compost and will be distributed again in the garden with the fertilizer next year and could cause a lot of damage.

Make nettle or tansy broth

A bed can also be watered with tansy or nettle broth as a preventive measure. This does not harm the plants, but helps with an infestation of root aphids as well as for prevention. You can make the broth yourself, but it is also available as a ready-made product in well-stocked gardening shops. In the case of in-house production, the procedure is as follows:

• Collect tansy flowers and whole plants in August
• dry
• Hang the bouquet upside down in a warm place
• Brew a tea from dried leaves
• let cool and add to the water
• Collect nettle
• mix one kilogram fresh with two liters of water
• boil and let cool
• Sieve off plant parts
• add to the irrigation water in a ratio of 1:10

The tansy, like the nettles, can also be freshly processed into a broth. About 1.5 kilograms of blooming tansy are mixed with ten liters of water, left to soak for 24 hours and then boiled.

Clean infested soil

The affected soil can also be cleaned. But this is only advisable if it is potting soil. Garden soil, on the other hand, can be removed and treated with systemic insecticides. However, if you want to be absolutely sure, replace the earth with new earth. The old one can be thrown away with the residual waste in well-closable garbage bags. Under no circumstances should this land in the wild, as the root aphids still in it could then spread here in a forest or on a field. The cleaning of bucket soil is as follows:

• Place infested soil in a microwave-safe bowl
• heat up to 700 watts
• microwave for about four to five minutes
• the lice should be killed that way

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