2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38
The black nutcracker, otherwise called wireworm, is found almost everywhere and reaches the western part of the steppe zone of Russia along river valleys. Its omnivorous larvae, although they prefer predation, regularly harm various agricultural crops, and vegetables in particular. Most often, potatoes suffer from the destructive activity of black clickers. The underground parts of vegetation eaten by these pests cause a significant decrease in the volume of the crop
Meet the pest
The black nutcracker is a beetle with a faint metallic tint, ranging in length from 10 to 14 mm. Female pests are slightly larger and rather flat. The top of these voracious parasites is black, with a long grayish pubescence, and the elytra sometimes have a brownish or yellowish tint. The lustrous, convex anterior dorsum of the parasites is slightly elongated and decorated with small punctures, and their sharp posterior corners are equipped with slender keels. The heads of the pests are densely and rather large punctured, and the forehead, slightly concave in front, sets off a slight edging along the anterior margins. Long antennae, starting from the third segment, are saw-shaped.
The size of the black-brownish larvae endowed with flattened cylindrical bodies reaches 27 mm. The last segments of their tiny bodies are slightly bifurcated, and the integument is colored reddish-brownish. Overwintering of uneven-aged larvae takes place in the soil at a depth of thirty to forty centimeters. And their pupation in the northern regions is observed in June, and in the southern regions - in May. As a rule, the development of pupae is kept within the period from ten to twenty-nine days.
The years of black cracker bugs coincides with the flowering of rye - these pests are often concentrated in huge quantities on the flowers of this culture. In the southern areas of the distribution range, beetles usually fledge in May, and in the northern ones - in June. Their additional food is vetch, alfalfa, rye and a number of other cultivated and wild grains. Each female lays an average of three hundred eggs, placing them in the soil at a depth of three to five centimeters. Oval small eggs of these parasites have a white-dirty tint, are practically indistinguishable in the soil and are covered with its small particles. The incubation period varies from 17 to 31 days, depending on the environment.
The development of larvae hatched in June is very long and takes over four years. During this period, they manage to shed 7 - 8 times. The hatching of the larvae continues until August. Their favorite habitat is loamy and sandy loam soils. Often these parasites can be found under the forest canopy, as well as in the soil of arable land. All larvae are omnivorous saprophages capable of predation. The full developmental cycle of black clickers takes about five years.
How to fight
An important place in the fight against black nutcrackers is given to various agrotechnical measures: observance of crop rotation, liming of soils, destruction of weeds, autumn plowing and thorough tillage. It is recommended to introduce crops such as mustard, flax and millet, which are slightly damaged by these parasites, into the crop rotation. In areas with perennial crops, soil disking is a good measure. The systematic application of fertilizers, especially ammonia and potash, is also encouraged.
As for the acidity of the soil, it is advisable to gradually reduce it - in neutral and alkaline soils, black clickers are almost never found. And in order to prevent their appearance, while digging the site, you can pour a little carbon slag into the ground.
Sometimes, after plowing the soil, black clickers are picked out of the ground by hand and destroyed. Since it is extremely difficult to crush them, the pests are simply torn apart. If the site is relatively small, it is quite possible to use this method.
Hay baits are also suitable for catching adults. With the onset of spring, small piles of hay or straw are laid out on the site. After a while, females will begin to climb under them in order to lay eggs. Once this happens, the traps are collected and destroyed.
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