In California’s Central Valley, citrus thrips are one of the most concerning pests for growers. Citrus thrips feed on young fruit, which results in scarring damage.
“Those cuts are then downgraded in the packinghouse, costing our growers money, which is why managing thrips is so important,” said Sandipa Gautam, University of California Cooperative Extension area citrus integrated pest management advisor.
This year, cooler spring temperatures have caused a bit of a delay in pest pressure. Thrips are present in orchards year-round, but they are most problematic after petal fall and into early summer. Warming temperatures will support pest development, with thrips producing eight to 12 generations in a year under the right conditions.
Gautam said the first step in monitoring efforts is sampling the outside canopy looking for immatures. “Repeat monitoring twice a week because they do develop pretty fast, so it’s important to do it frequently,” she advised.
Understanding the difference between citrus thrips and western flower thrips is an important component of monitoring efforts. Flower thrips are longer and thinner and will generally leave an orchard after petal fall.
Treatment thresholds for citrus thrips will be dependent on the citrus variety as well as the growing conditions.
“Use soft chemistries that have less effect on natural enemies. Predatory mites are pretty active around this time of the year and do contribute to thrips management, although they do not completely control them,” said Gautam. “Thrips are more of an outside canopy pest. So, focus on outside coverage and only treat when needed.”
As growers treat more than once, alternating chemistries will be important to help delay resistance development in thrips populations. “Some of the products that have been used in the past year as standard materials are Minecto Pro, Agri-Mek, Exirel and combinations of those,” Gautam said.
Source: AgNet West