Among the various pests of the orchard there are some generic ones and potentially harmful to human health, namely wasps and hornets. The damage that these insects create to the orchard is the laceration of the fruits, since they search for the sugars contained in the pulp, while we, as is known, can be stung with discomfort and in particular greater risks in allergic subjects.
Those who have fruit plants in the garden in particular risk ruining the opportunity to live the outdoor space peacefully. With some precautions, however, you can limit its presence so that you can live with it, without having to use chemical pesticides.
Wasps and hornets are insects of the order of the Hymenoptera, to which bees also belong, and like them they have a social organization, although less evolved. However, we must know how to recognize bees and protect them, because they are very important pollinating agents, useful both for fruit plants and for the environment in general.
Recognizing wasps and hornets
There common wasp and the German wasp they are the two most common wasp species in Europe. Both have yellow and black bodies, with markings that vary between one and the other, yellow legs and sizes ranging from 12 to 17 mm in the workers, while in the queens they reach 2.5 cm.
In addition to the common wasp, there is also the "social wasp" or vespula which measures 1.25 cm (worker) and 1.9 cm (queen), has two sets of wings and is in alternating yellow and black stripes. Despite the similar color it is easy to distinguish wasps from bees because the latter have a slightly stockier body than the former and the yellow of their body is darker.
The hornet (Vespa crabro) belongs to the same family as the wasps but is much larger and for this reason it is also called "giant wasp". The body of the female can reach a length of 5 cm, while the males and the workers stop at 2-2.5 cm.
Nesting and behavior
Wasps can form their nests in natural environments such as hollow trees and bushes, but they also tend to take advantage of domestic environments such as ceilings, gutters and various cavities, as long as they are sheltered environments with easy exit routes. Wasps do not produce honey like bees and live by eating the meat of other insects and sugary substances. When these insects perceive a threat, they use their sting as a defense weapon by stinging and emitting poison. Unlike bees, which sacrifice themselves to sting and then attack as a last resort, wasp and hornet can strike more than once.
Many people are allergic to the venom of wasps and hornets, which is why their stings are potentially dangerous. In the presence of these insects, it is therefore advisable to remain calm and avoid waving your arms in an attempt to chase them away because this gesture could attract their bites.
Hornets' nests are quite large, spherical in shape and capable of generating 300-500 specimens or more. It is advisable not to approach these nests, once identified, because the hornets can attack even without explicit threat, being attracted by human sweat.
The damage of the wasps to the orchard
The damage that wasps and hornets cause in the orchard is linked to their search for sugary substances, for which they feed on fruit which is heading towards ripeness, creating lacerations and exposing it to rot and secondary parasitic attacks. The affected species are many, especially those that produce fruits with a high sugar content: figs, pears, grapevines, peaches and others.
Reduce the presence of wasps and hornets
Of course, there are many insecticides capable of eradicating the populations of these insects, but in order not to pollute the environment and not to risk killing even beneficial insects, it is necessary to resort to other more eco-friendly methods. The advice is to focus on the prevention of wasps.
One of the best ways to limit the development of wasps and hornets in a very consistent way is the installation of food traps, such as those of the Tap Trap type. These bio traps update an old peasant method of trap with bait, they consist of special yellow plastic hooks that hang from the foliage of fruit plants with bottles filled with bait attached.
For the traps to be truly effective, it is very important to place them at the end of winter, at the latest in early spring and not wait for the fruits to be protected on the plants. Being timely allows to prevent the reproduction of these insects and to drastically reduce the number of queens in the environment, and consequently the nesting. By knocking down their reproductive rate thanks to this timing, from year to year we can see significant decreases in their populations: considering a number of 300-500 individuals generated by a queen (but often even more) we can understand how important it is to avoid that this you get to reproduce.
In March, when the fruit trees are still leafless, the yellow color of the trap stands out clearly and attracts the few specimens of wasps already in circulation. Putting the traps when the fruits are developing on the plants or even are towards ripening is not effective because even if many hornets and wasps will end up in the traps attracted by the baits, just as many will go on to eat the fruits, with consistent damage.
If you put the traps in early spring, the catches will be low: 4-5 insects per bottle in 2 or 3 weeks. In fact, these few insects that fly in the spring are probably queens, and it is very important to catch them before they can reproduce. Catching a single queen in spring has the effect of significantly reducing the presence of wasps and is more effective than having traps full of wasps during the summer.
From time to time it is useful to take a monitoring tour in the orchard and check the catches made and the state of the baits.
Baits for wasps and hornets
The best baits to put in the traps in early spring are the sugary ones, because the wasps come out of the winter, they are fertile, and they have to recover their strength to go in search of nesting spaces. So in the Tap Trap we can put beer or water, vinegar and sugar.
Here are three recommended recipes for catching hornets and wasps:
- Beer trap: 350 ml of beer and 2 tablespoons of honey or sugar.
- Vinegar trap: 200 ml of water, 2 tablespoons of honey or sugar and a glass of red wine vinegar.
- Mint trap: 350 ml of sweet white wine (or sweetened with sugar or honey) and 20-30 ml of mint syrup.
The renewal of the bait
About every 15 days it is important to renew the bait, otherwise it loses its effectiveness and on the contrary exerts a repellent effect, because the corpses of all the captured insects give off bad smells.
The Sfera Trap: summer remedy
Food traps are a good spring remedy, when summer approaches, wasps and hornets look for protein rather than sugary substances. This is because it is no longer the queens that circulate, as they are found hatching, but the workers who go out to get food to bring to their offspring. This is also the reason why wasps attack apiaries, killing bees and bringing them to the nest for food.
For this phase of the season you can try the Sfera Trap traps, which are made in a yellow sphere, are bright thanks to a LED that runs on batteries that last for about a month. These traps are therefore effective both day and night. Before hanging them, we need to cover them with cling film and then sprinkle them with glue, so that the insects, which approach attracted by the yellow color, remain attached. It is best not to use this trap during flowering periods to avoid the risk that it will also attract bees, bumblebees or other beneficial insects.