The walnut tree is a very long-lasting plant with majestic foliage, and its cultivation is considered among the most profitable in the world. Its fruits, the walnuts, contain highly nutritional properties; they are harvested in the autumn and are the basic ingredient for many culinary dishes. Unfortunately, the harvest of this fruit can be put at risk by the attacks of pests, and particularly by harmful flying insects, which compromise the qualitative and quantitative productivity of walnuts.
To prevent and treat walnut diseases with eco-friendly and sustainable methods, it is important to identify the type of flying pests attacking this fruit and follow the correct method of mass trapping - which includes placing the traps at the beginning of the season.
WALNUT DISEASES CAUSED BY FLYING PESTS
Black and mushy walnuts are the most common result of the damage caused by the walnut husk fly. The husk fly stings the hull and lays up to 400 eggs, which hatch in a few days and develop in just over a month; then the hull blackens, disintegrates and remains only partially adherent to its shell, which is also black stained; the diseased fruit then falls.
The musty kernel, on the other hand, is the damage caused by the carpus: the larva of this Lepidoptera, which looks like the classic worm that we find in diseased nuts, attacks both the young shoots and the fruits. Its presence can also be recognised by the dark granular clusters on the fruit hull, which is nothing but the waste expelled by the larvae as they dig inside the fruit.
WALNUT HUSK FLY TRAPS AND CARPUS TRAPS
The eco-friendly insect traps offer a good level of protection to the walnut tree from the husk fly and the carpus, thanks to their continuous mass trapping until the end of the season. Furthermore, bio-traps significantly reduce the use of pesticides. They should be placed on the parts of the tree that are most exposed to the sun (one or two traps per tree) and they should be checked and renewed every 15-20 days, thus making sure that the the bait is always effective.
Baits for the Carpus can also be homemade: the most suitable attractant for capturing this Lepidoptera is made mixing water with vinegar and sugar.
Click on the trap here below to discover the right recipe for mas trapping the insect that causes the damage.
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