The aphid is, by far, one of the most known pests by farmers, affecting a very large number of species of plants, shrubs and trees. However, within the aphids, as they are also known, there are many species that can be more specific when attacking certain crops. This is the case of the black aphid or black aphid of legumes , as it is also known.
Its main differentiation? The black color of its entire body compared to the usual green tones of the common aphid or cotton aphid ( Aphis gossypii ). Its other features? Its great resistance to insecticide treatments.
And this is one of the great problems facing farmers today. Not all products are effective for all aphid species because there are differences in feeding behavior and morphology of each one of them.
This article is focused on getting to know the black aphid ( Aphis fabae ) in depth , learning to identify it and knowing the time when it reproduces, the parts of the plant where it usually attacks and some means to combat it.
WHAT IS THE BLACK APHID ( APHIS FABAE ) LIKE?
The first and most important thing going fully into the article is a simple identification guide. Of all the classes of aphids that affect crops, Aphis fabae stands out for its intense black color throughout the body, something that makes it easy to identify since it offers a great contrast with the green of the plant and the new shoots where it is usually locate.
The black bean aphid mainly affects legumes, since it has a special predilection for the sap emitted by these plants. However, it affects a large number of crops, generally horticultural.
Not all black aphids are Aphis fabae . For example, the main black cherry aphid is also this color and is classified as Myzus cerasi . Therefore, the control strategies of this insect are different from those of Aphis fabae .
And if that wasn’t all, the aphid cycle is very diverse. Aphis gossypii Glover , which affects many species, including citrus, has a stage in which the adult female ape also has a black body.
HOW IT AFFECTS PLANTS
Of all the versions of aphids that we can find in agriculture, the behavior in plants is the same in all of them. They suck the sap through their stylet to extract all the cellular juice. When we talk about high populations, the volume of sap extracted may be higher than that manufactured, so it slowly weakens until it causes the total collapse of the plant.
In addition, cell juice contains many sugars, which causes a sticky appearance on the leaves that attracts other insects (ants) and fungi such as sooty mold or bold, as it is often known.
A more serious problem than most aphids, including Aphis fabae , they are virus transmitters , especially in potato, beet and tobacco crops.
The main parts of the plant affected by the black aphid are, as with the rest of aphid species, the new shoots and the most tender parts of the plants. It is much easier to access and extract the sap, since these shoots act as a sink for the plant, which means that a large part of its resources (sugars and photoassimilates), go to these new shoots and newly formed leaves.
QUICK AND EASY IDENTIFICATION IN LEGUME PLANTS
If we have cultivated legume species and see black-bodied insects on the new leaves and shoots, there will be little room for error when classifying the aphid as a black aphid ( Aphis fabae ). For this reason, their identification is extremely simple, since they are between 2 and 3 mm in size, which are perceptible to the naked eye and offer a great contrast with the green of the plant.
On the other hand, unlike other aphids, such as citrus aphids, the black aphid does not roll new shoots as a result of the suction of sap, except in the case of the beet plant . Therefore, the symptoms must be found by difference and color contrast, something easier than even detecting the deformed leaves themselves.
HOW TO COMBAT BLACK APHIDS
Not all active ingredients against the genus Aphis are equally effective for black aphids. Currently there are not many authorized products, the most famous being the active ingredient Acetamiprid and Deltamethrin.
However, in accordance with respecting current regulations and being up-to-date, it is advisable to consult the currently authorized products, which are the ones we offer in the following link.
Read more: products authorized by the Ministry of Agriculture of Spain .
ORGANIC PRODUCTS AGAINST APHIS FABAE
Although the black bean aphid is a fairly resistant insect, foliar treatments applied directly to the pest with potassium soap are effective if we follow a strategy of repetitions every 3-5 days.
These soap-based products work by degrading the protective layer of the insect and eliminating the nymphal stages or eggs that may be in the plant. Depending on the concentration of the product, the recommended doses are the following: