Swellies are pests of a beetle species that feed on many ornamental and fruit plants. It is not uncommon for their occurrence to cause plant death
Swellies are beetles in the shrew family. Adults of this species are about 1 cm long. A characteristic feature of these beetles is their dark brown or black carapace. Swell beetle larvae overwinter and feed in the soil and are grayish-white in color. They feed in the fall and winter even at temperatures around 0 degrees – biting the skin off the tree or shrub from the root to the base of the trunk. In spring, the larvae transform into adults, and after 4 weeks the female is ready to lay up to 1,000 eggs.
The most common species of swellings:
These beetles most commonly feed on:
Swell beetles damage not only the leaves – they bore characteristic holes in them from the edge, but also the bundles and bark of young shoots. These beetles attack only the lower parts of plants. It is very easy to recognise the damage they cause – round holes on the edges of the leaves.
Unfortunately, you cannot see the damage done by the leaf beetle larvae and very often they lead to the weakening and death of the entire plant. A plant infested by leaf maggots looks as if it will wither in spite of proper care. When the ‘dried’ plant is dug up you can see that the roots are bitten off and have small greyish-white larvae on them.
Controlling these beetles is a very difficult task – they feed only at night and are invisible during the day. The most effective control is from March to May and from August to October.
It is worth taking care of the presence of natural enemies of these beetles in the garden, and these are:
When using chemical plant protection products, you must strictly follow the manufacturer’s recommendations, while exercising maximum caution. Chemicals are very harmful to human health and the environment.
To fight larvae, concentrates are a good solution to use when watering the plant. Preparations for controlling larvae are:
To combat the adults are best sprays, which should be applied after sunset. The treatment should be repeated every 2 weeks. Preparations that control the adults are:
The plants should not only be sprayed but also watered with solutions designed for this purpose. Downy mildew hides in the soil. The best time to treat is in spring, when the larvae come to the surface and the adults come out of their winter hiding places
Nematodes are the “natural enemy” of swellings. A nematode treatment such as Larveran should be applied twice a year in spring (April/May) and in late summer (August/September). Nematode treatments must be applied to damp soil. During application, the soil temperature should not be below 14°C. Products containing nematodes kill only the larvae; adult nematodes are ineffective.
Swellies are one of the most dangerous pests for plants – they cause them to “dry out”. It is advisable to prevent swellings by using preparations with nematodes.