They are small, brown and can cause great damage: raspberry beetles. But you can easily fight this bug with our three tips.
Most hobby gardeners who have raspberries in their garden will meet the raspberry beetle at least once. This belongs to the family of flower eaters and is one of the most important pests of raspberry plants. However, he not only attacks raspberries, but also blackberries, cherries, plums, pears and apples.
The hairy, greyish pest only reaches a size of just five millimeters and gets to the fruit plants through weeds, especially dandelion. The development of the larvae then takes place directly in the fruit. They then become mad, so to speak. Too bad, because what could be more delicious than raspberries from your own garden? So don't let the berries get maggots and fight this pest.
The development of the raspberry beetle
The beetle hibernates in burrows and then resurfaces in May. If the weather is mild enough, the flying beetles will land on the blossoms of the fruit plants. They then nibble on them and feed on them. After the females have been fertilized, they lay a single egg in each flower. And such a female raspberry beetle can easily produce a few hundred eggs, so that a large number of flowers are usually affected.
After about 10 days, when the berries are slowly turning red, the larvae hatch from the laid eggs. They now feed on the particles within the fruit. After eight weeks at the latest, the larva is fully grown, drops to the ground and buries itself. The larvae then pupate in a cave about 30 centimeters deep, which lasts until autumn. Then the beetle hatches and appears above the ground next spring.
So you can see that if you don't fight the raspberry beetle, this is a cycle that will always produce offspring. Below is a detailed description of the phases of damage caused by the raspberry beetle.
Phases of damage by the raspberry beetle
First, the adult beetles attack the buds andto create raspberry blossoms. This means that the berries later remain quite small or are deformed. The pests bite off entire stems and eat entire buds, leaving only the sepals. This is followed by the second phase, when the larvae hatched from the eggs eat the fruit from the inside. As a result, some of the fruits turn brown. Only the undamaged partial fruits continue to ripen and take on the red colour.
The feeding damage of the beetles can be clearly seen during the flowering period. But at the latest when you see the deformed and unappetizing raspberries, it is clear that the raspberry beetle was at work here. You should therefore regularly check your raspberries for infestation and take immediate action if you spot the raspberry beetle.
Tips for controlling the raspberry beetle
Once you have noticed the infestation, you should do something about it, otherwise you will suffer a major crop failure. And you can do it like this:
➤ Tip 1 - stretch foil:
Prevention is still best, so it's best to stretch black sheeting (or garden fleece) over the ground. If the larvae fall down now, they don't have a chance to burrow into the ground and pupate. So a new generation is reliably prevented. The beetles, on the other hand, which are already developing in the ground, then have no opportunity to see the light of day in spring.
➤ Tip 2 - Shake off bugs:
If you spot bugs on your raspberry plants, you can also try to shake them off. Sometimes this also works with the larvae in the fruit.
➤ Tip 3 - Inject plant poison:
If you use plant poison, then you have to consider that this harms people and animals and the fruits are therefore no longer edible. If such use is unavoidable, you should spray some plant poison once before flowering and again afterwards.
Important: Under no circumstances apply such agents when bees are on or on the plants.