Scirtothrips citri

    Citrus fruits play an essential role in the global production of fruit trees, resulting in a significant economic, social and cultural impact in our society. In real time, citrus fruits are widely distributed around the world, asthey are found in more than 140 countries thanks to the development of the citrus sector.In nature, living things interact with each other, either positively or negatively.Citrus thrips among the serious insects on fruits in this article introduce us to the general description of Scitothrips citri, the damage on fruits and the methods of control.

·         Description

Citrus thrips are characterized by their small size and yellow-orange coloring, as well as the presence of fringed wings. Females range in size from 0.6 to 0.88 mm. Males have a similar appearance, although they are slightly shorter and narrower. Under heat conditions, citrus thrips can survive for 25-35 days or longer in cooler environments.

The eggs, measuring 0.2 mm, are deposited under the cuticle of young leaves, stems and fruits. A female is able to lay up to 250 eggs. Hatching occurs within six to eight days during the summer season.

Two active larval stages are identified, requiring a development period ranging from 4 to 14 days. Initially, the larvae actively feed on the tender leaves as well as on the fruits, especially under the sepals of the young fruits. The third and fourth stages represent phases of puposis during which individuals do not feed. They continue their development in the field, whether in the litter under the tree or in its crevices. Between eight and twelve generations can succeed each other in the course of a year.

·         Damage

Citrus thrips have a wide variety of hosts. It is the most economically damaging insect pest for citrus crops in Arizona. On fruits, lesions caused by bites of epidermal cells manifest as grayish or silver scars on the surface of the crust. Larvae of the second larval stage are particularly harmful, as they feed mainly under the sepals of young fruits.

These stings can alter the quality of the fruits and, in the event of a severe attack, they can make them unfit for consumption as is.

·         Surveillance

The monitoring of citrus thrips begins at the beginning of flowering, but is of crucial importance during the fall of the petals, which reaches 90%. Sampling should continue until 70-90% of the fruits reach a minimum size of one inch in diameter. Once the fruit has reached this size, it is no longer vulnerable to attack.

It is recommended to take between twenty and fifty samples in order to obtain an accurate estimate of the citrus thrips population. Treatments should be given when 10% or more of the fruits show signs of infestation.

·         Rational

Citrus thrips populations show a tendency to grow following the application of insecticides that have the effect of eliminating predatory mites. Citrus thrips quickly acquire resistance to chemicals repeatedly used for their control. Given the limited number of pesticides available for the control of citrus thrips, it is imperative that producers carefully monitor the levels of these pests to avoid unnecessary treatments. In addition, it is recommended to avoid successive applications of identical or similar insecticides.