Eastern Fruit Moth, a Dread on Stone Fruit Trees

The Eastern Fruit Moth, Grapholita molesta is a Lepidoptera that appeared in Algeria on peach and nectarine orchards in the Mitidja plain during the last 10 years (between 2010 and 2011). It can also attack apple and pear trees as observed in the Ain defla region in June 2020.

The attacks of this pest are becoming more and more remarkable over the years, especially with the frequent return of dry seasons.
The attack begins with the deposition of eggs on the underside of the leaves located at the end of the shoots or next to the fruits. As soon as the emergence from the egg occurs, the young caterpillar penetrates the young shoot (Fig. 1).

As it drills its descending gallery, the caterpillar rejects its excrement around the orifice. By blocking the elongation of the shoot, the number of fruits per mixed branch is reduced, which will influence the number of fruits per tree.

While the pest is scarcely studied in Algeria, the appearance of the first adults (butterflies) from the overwintering generation takes place, for the Mitidja, at the end of March-beginning of April and can last for 2 months (Fig. 3). The third generation usually attacks peach and nectarine.

The pest presents several generations a year.

The oriental fruit moth genome provides insights into evolutionary adaptation of tortricid pests – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/mage-of-four-stages-of-Grapholita-molesta-Egg-a-larva-b-pupa-c-adult-d-the_fig1_344162642 [accessed 10 Jan, 2023]

Oriental fruit moth control requires a program that combines prophylaxis and chemical control.

As prophylactic measures it is necessary:
• Take action in winter to control overwintering forms.
• Monitor bark crevices to remove diaponent caterpillars on trees affected the previous year.
• When thinning fruit, select affected fruit.
• Install pheromone traps to effectively determine the treatment period.
• Eliminate affected fruits to reduce the population of new generations.

For chemical treatment, active ingredients approved against other fruit tree miners such as codling moth are effective, for example chlorpyrifos, imidachloprid (IMIGUARD 20% SL), cypermethrin, lambda cyalhotrine and lunefuron, against this moth.