The months of March and April are favorable for ferrets and fruit flies

Ferrets and fruit flies are pests that cause direct damage to citrus fruits, causing rot and fall. These pests occur throughout the year, with the months of March and April being favorable for their appearance and, therefore, require monitoring and management measures in order to avoid economic damage.

Research indicates that the best strategy is to monitor both pests early, to detect the presence of these insects in the orchard and monitor the population until control levels are reached, avoiding fruit loss.

Ferret  

The ferret bug (Gymnandrosoma aurantianum) lays its eggs in flag and ripe fruits, causing them to rot and fall. When the infestation is early and populations are high, green fruits can also be attacked.

Damage to fruits attacked by the ferret can be diagnosed by the presence of the caterpillar's entrance hole, which is surrounded by yellow color. Furthermore, after penetrating the fruit, excrement and food remains are released from the hole in the skin, and the affected area of ​​the fruit becomes hardened. The caterpillar, cream to brown in color, has lines formed by bristles, as well as spots on its back.

To monitor ferret adults, a method was developed using sex pheromone released in tablets, inserted into a delta trap, which attracts males and allows decision-making about management.

Next, it is necessary to count the catches and check the action levels to define the control strategy that will be used, which can be done with chemical products for moths and caterpillars, ebiologicals or insect growth regulators targeting only the caterpillars.

Monitoring the pest must be carried out especially targeting the adult population, explains Fundecitrus researcher Haroldo Volpe. “In this way, we can adopt control measures focused on moths – a target exposed on the tip of the plant mainly at dusk –, preventing the females from laying eggs in the fruits and preventing the caterpillars from hatching and entering, causing damage, rotting and falling of the fruits. . This is also important because the pest has very rapid population increases, in addition to the fact that monitoring based on the number of attacked fruits has the disadvantage of taking control decisions only after counting already damaged fruits, generating economic losses and losses for the citrus grower” , complete.

fruit fly

Two species of fruit flies attack trees in the citrus belt and cause fruit to fall: Anastrepha fraterculus, which has more intense infestations between the months of March and May, covering the fruiting period of early citrus varieties, and Ceratitis capitata, which occurs mainly from July to November, attacking mainly the semi-late and late varieties.

Anastrepha fraterculus oviposits on small to mature green fruits; while Ceratitis capitata has a preference for green fruits at their maximum size until they are ripe. The area attacked by the flies becomes soft and rotten and the larvae's exit hole – which has no legs and is white or yellowish in color – is visible and easily identifiable.

Differentiating the attack of ferrets from fruit flies can cause doubts. “It is important to be aware of the differences to correctly identify the pest in question and choose the appropriate control method”, emphasizes Volpe.

Monitoring of fruit flies is done by capturing adult insects, using McPhail model traps with a food attractant that attract both species or a Jackson model with parapheromone, which attracts only C. capitata.

The analysis of the traps will guide the control, which is done with attractive baits containing insecticides applied in alternate streets and in areas no larger than one square meter from the center of the tree canopy.

Furthermore, it is important to remove fruit infested by ferrets or fruit flies from trees and fallen to the ground and destroy them.