Estimation of the infestation rate and parasitism rate of the citrus leafminer Phyllocnistis citrella in a Thomson orchard near a greenhouse where beneficials are reared in Boufarik-Blida (Algeria)

Abstract

The citrus leafminer Phyllocnistis citrella causes severe damage to young citrus shoots in Algeria. It therefore indirectly delays fruit set and consequently production and crop profitability. The endophytic lifestyle of the insect's larvae has made chemical control difficult, making the use of other control agents essential.
 To this end, a study on the population dynamics of Phyllocnistis citrella and the incidence of the parasite was carried out for 08 months in 2021 (from January to August 2021) in the Boufarik-Blida region (Algeria) on the Thomson variety.
 The main results gathered from the sampling show that the parasitism rate reached 68% and the infection rate 39%, due to the intervention of auxiliaries (Semielacher petiolatus, Cirostichus phyllocnistoides) from the greenhouse where these species are reared near the Thomson orchard. The citrus leafminer population is declining. Parasite brokering has a positive effect on the defense against Phyllocnistis citrella and represents an effective method of reinforcing biological control of this pest. In addition, the installation of mini greenhouses for the rearing of beneficials in orchards infested by citrus leafminer can be proposed as a means of reinforcing biological control. Moreover, regional containment is a healthy alternative in the context of integrated pest management, helping the ecosystem to reduce pollution. For this reason, it is worthwhile scheduling containment periods in agricultural regions.