Management of Thrips Species in Citrus Groves in the Marrakech Region: Exploring Biological Control Methods as Alternatives to Chemical Methods

Abstract

Thrips, which historically caused minimal damage to Moroccan citrus orchards, have become a significant concern since 2018. A study was conducted from March to July 2021 in a citrus orchard in the Marrakech region and aimed to identify thrips species and natural enemies, monitor population dynamics, and evaluate alternative control methods. Two trials were conducted on the effect of several products on thrips species in the citrus orchards; the first one (chemical trial) where Flonicamib, Spirotetramat, Formetanate, Acetamiprid, Cyantaraniliprole, and Abamectine were assessed, the second trial (biological control), Pyrethrum, Neem oil, Beauveria bassiana, a mixture of Azadirachtin and paraffinic mineral oil, a mixture of Pyrethrum and neem oil, and a mixture Pyrethrum and zadirachtin were evaluated. Six thrips species were recorded: Frankliniella occidentalis, Thrips tabaci, Pezothrips kellyanus, Scirtothrips sp., Aeolothrips sp., and Haplothrips sp. Population peaks varied by citrus variety, with adult thrips reaching their highest levels during petal fall for clementine Nules (4 ± 1 individuals/beating) and during summer shoot growth for mandarin Afourer (8.8 ± 1 individuals/ eating), while larval populations peaked 10 days later on Nules but remained low on Afourer. Four predatory; Coccinella septempunctata, Orius sp., Chrysoperla carnea, and Aeolothrips sp. were found on citrus trees and their population peaked during petal fall. Formetanate sowing the highest efficacy (88.7% after 3 days), while Spirotetramat was less effective to control thrips species. Beauveria bassiana and the mixture of Azadirachtin and paraffinic mineral oil were two treatments that showed the highest significant efficacy (75.9% and 78.82 %, respectively, after two weeks). These findings underscore the increasing threat of thrips species in commercial Moroccan citrus orchards and highlight the potential of integrated pest management strategies that combine chemical and biological control for sustainable thrips management.