In the plum orchards in the vicinity of Kragujevac and Topola, the beginning of egg laying of the pest known as plum curler was recorded. It is precisely because of this development that it is necessary to continue protection against fungal diseases, PSSS Kragujevac announced. Chemical measures, however, are not recommended in plantations where harvesting has already begun.
Tomasz Klejdysz
The current state of plums in Šumadija
In the plum trees in Šumadija, the Stanley variety has not yet arrived for picking. The fruit is currently about 70% of its final size and starting to take on color. The harvesting of the Čačan beauty is in progress, while the harvesting of the Čačan best has just begun. Counselors from the PSSS Kragujevac warn that the laid eggs of the third-generation plum curler were registered by visual inspection. Producers of late varieties, such as Stanley, are recommended to be treated with adequate ovicidal agents. The choice of insecticide should be coordinated with the start of the harvest of Stanley, in order to respect the waiting period.
Protection of fruits from rot
During fruit ripening, the skin softens and there is an increased risk of infection by rotting agents. Infection is possible if the plums are mechanically damaged by hail, wind or insects. Producers must pay attention to this fungal disease because it has quarantine status in the countries where our fruit is exported, PSSS Kragujevac announced. To protect against fruit rot, fungicides based on fludioxonil, amboxalid or pyraclostrobin are applied. Treatment is recommended in the evening hours due to high daytime temperatures, and in plantations where harvesting is in progress, chemical measures are not recommended!
What is a plum roll?
Plum borer is one of the most important pests of plum. The most harmful stage of this pest is the larva, which causes enormous damage in conditions of overpopulation, which often occurs in favorable climatic conditions. First-generation butterflies lay their eggs in young fruits after flowering, when the fruits reach the size of cherry pits. After leaving the egg chorion, the young larva wanders around the fruit and then burrows into its interior. The attacked fruit stops growing, turns purple and falls while the larvae are still small.
A drop of resin appears at the point of puncture, and one fruit can be punctured by several larvae. The larvae often damage the stone in the young fruit, and the holes around the stone are filled with their excrement. The flight of the second-generation butterflies begins in mid-July, and they lay their eggs in ripening fruits, while the fruits are still green, but have reached their maximum size. The larvae bore into the fruit and feed on the flesh of the fruit. The biggest damage is caused by caterpillars of the second generation.
The life cycle of the plum curler
Plum curler has three generations a year. It overwinters as an adult larva in a cocoon in the bark of lower branches and trees or on a plant substrate on the ground surface. Metamorphosis into a pupa occurs in early spring, usually at the end of March, and the butterflies hatch in April, May and early June. Butterflies of the overwintering generation lay eggs in young fruits 3-4 weeks after flowering. Oviposition occurs in warm and quiet weather, without wind. The female lays an average of 40-50 eggs. After sawing, the larvae bore into the fruit and feed on the flesh of the fruit around the seed, whereby several larvae can bore into one fruit.
After 4-5 weeks, the larva reaches its full development and leaves the fruit, going into the cracks of the bark at the base of the trunk or into the plant substrate on the surface of the soil to pupate. The pupal stage lasts 10-13 days. The flight of butterflies of the first summer generation begins at the end of June, and they lay their eggs on ripening fruits. The peak of the summer is from the beginning to the middle of July. The flight of butterflies of the second summer generation lasts from the beginning of August to the middle of September. Summer generations overlap. Incubation of the eggs lasts 6-11 days, then the larva emerges and crawls into the fruit. The larvae feed on the flesh of the fruit and after 20-24 days they reach their full development, after which they leave the damaged fruit and go under the bark of the tree where they spin a cocoon for wintering.
Sources: Good morning, Agronomy
Source: boljazemlja.com
