Citrus growers cautioned to prevent pest outbreaks

Citrus growers are being urged to act swiftly to suppress false codling moth (FCM) populations rather than focus on fruit protection after an outbreak has occurred.

Dr Sean Moore, an entomologist at Citrus Research International (CRI), said it was strongly recommended that growers initiated FCM control measures early in the 2018/2019 season.

“The best approach to FCM control is population suppression, not just fruit protection, which is most effective when pest levels are at their lowest, thus preventing them from increasing. We now have a golden opportunity to effectively suppress FCM populations while they are at a very low level.”

Moore recommended several practices to suppress FCM populations. “Immediately after harvesting in an orchard is completed, all fruit remaining in the orchard [hanging and on the orchard ground] must be removed and destroyed. This would remove the bridge for FCM to [be transferred] from one season to the next. Trees should be thoroughly pruned to maximise the opportunity for optimal spray coverage and penetration during the course of the following season. A granulovirus spray applied after the spring FCM flight peak can significantly improve FCM control, [instead of] only initiating such sprays after the November/ December flight peak.”

Meanwhile, the Citrus Growers’ Association of Southern Africa (CGA) cautioned farmers to strictly adhere to maximum residue level (MRL) requirements for export markets. During the past year, CGA received at least three reports of consignments of fruit being rejected in Taiwan when residue levels of plant protection products were detected. In all these cases the levels were very low, but were detected with highly sensitive equipment, or as a result of cross-contamination, CGA said.

CGA urged growers to exercise care when using chemical sprays, as there were high costs associated with product rejections in Taiwan, and continued access to this market needed to be ensured. In addition, South Korea was moving to a positive MRL list system that would be coming into effect on 1 January 2019. While the number of MRLs implicated for citrus exports to South Korea were few, the impact was significant, particularly from a citrus black spot management perspective. Growers were therefore urged to be cautious if they had used or intended using any of the following active ingredients on fruit being prepared for export to South Korea: dithiocarbamates (Dithane/Mancozeb), Benomyl/ Carbendazim, Fosetyl-Al (Aliette), Dichlorprop (Corasil) and Etoxazole (Smite). – Lindi Botha

FW ACHIVE BELOW: Outbreaks of false codling moth infestations in citrus orchards can be prevented by taking the necessary precautions, according to Dr Sean Moore, an entomologist at Citrus Research International.