Diseases And Pests Of Plum: Plum Gall Mite

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

The plum gall mite causes irreparable harm to the plum with thorns. However, almonds and peaches often suffer from its invasions. Near the bases of the shoots of the first and second years, reddish-brown galls gradually form, subsequently acquiring the same shade as the shoot bark. Gradually growing together, the galls fold into rather large growths, inside which ticks quickly settle. Often, in the habitats of these harmful insects, the yield is halved. And when they are repopulated with them, the plants die within the next few years

Meet the pest

The plum gall mite is a small, bizarre, cylindrical mite. On its opistosome, as in all other four-legged gall mites, one can notice six to seven pairs of setae. And the oral apparatus in pests is of the piercing-sucking type.

Adult females overwinter in numerous galls located near the bases of the buds. Often, in a single gall on a plum, you can find from one hundred to four hundred ticks, and on an almond, their number reaches four to five thousand.

In the spring, as soon as the plum fades, and the air warms up to fifteen to seventeen degrees, harmful parasites will leave the wintering sites and begin to crawl behind the kidney scales or into the folds formed after they fall, located near the bases of the growing shoots. The release of vicious ticks from wintering places takes about two weeks, and this process is fully completed towards the end of May or at the beginning of June. During this period, ticks are incredibly active and most vulnerable to the action of all kinds of pesticides, since they lead an extremely open lifestyle. Approximately at the beginning of June, fresh galls that look like tiny red bumps are formed on fruit trees under the influence of special enzymes secreted by harmful parasites when sucking. And after a while in these galls you can find hidden females, the eggs laid by them and voracious larvae.

Spermatophore reproduction is characteristic of harmful plum mites. Spermatophores are left by males on the tops of leaf blades, as well as in many other places visited by females. Females, crawling along these areas, capture the left spermatophores, then press them with the help of genital valves and immediately transfer their contents into the spermatheca. Non-inseminated females lay eggs, from which males emerge, and females always revive from the eggs of inseminated pests. In this case, the development of eggs takes place within the maternal galls. There, nymphs of both the first and second instars develop, as well as adults, which also overwinter inside the maternal galls.

Towards the end of July, the galls acquire a characteristic spherical shape and grow to 1 - 2 mm in diameter. And with the onset of autumn, they darken, grow together in several pieces and are painted in common tones with tree bark. The result of the harmful activity of gluttonous parasites is the formation of rather ugly and very unpleasant growths.

During the summer, several generations of pests have time to develop. It is noteworthy that all offspring continue to live in the maternal Gauls. And during the transition of harmful parasites from one stage to another, short periods of rest are observed.

Most often, these evil insects can be found in areas of beech forests and beautiful birch groves, as well as in plum orchards located in the steppes.

How to fight

Fruit trees attacked by harmful parasites immediately after flowering are recommended to be treated with solutions of tedione or colloidal sulfur. And with a particularly severe lesion, the treatment should be repeated after ten days. In addition, branches that are too badly damaged must be cut and burned promptly.