Early Bloom and Elevated Thrips Pressure in Citrus
Citrus bloom has now ended across much of the San Joaquin Valley, nearly three weeks ahead of the historical average. In Tulare County, monitoring confirmed the presence of both immature and adult citrus thrips actively feeding on young fruit. This early activity is likely driven by a warmer-than-normal winter followed by an intense heat wave in March, accelerating pest development and shifting seasonal timing for key pests including citrus thrips, California red scale, and citrus mealybugs.
As of April 1, thrips were detected on 24% of sampled fruit, indicating early and higher-than-normal pressure. Growers have already begun applications to protect fruit from scarring damage. With continued warm conditions, no rainfall in the forecast, and low levels of predatory mites, thrips populations are expected to develop rapidly. Experiences from previous seasons show that the currently available pesticides do not have long residual activity. Therefore, close and frequent monitoring will be critical to guide timely management decisions and avoid economic damage caused by thrips.
Note on Piperonyl Butoxide (PBO):
The California Citrus Quality Council has issued an advisory regarding the use of piperonyl butoxide (PBO), also marketed as Reform® and Exponent®. Currently, there are no established maximum residue limits (MRLs) for PBO in Korea. Therefore, growers and PCAs are strongly discouraged from using PBO on acreage that may be destined for export to Korea, as applications could result in residue violations and potential shipment rejections.
CCQC is actively working with registrants to establish MRLs for PBO; however, there is currently no timeline for approval. In the meantime, growers should avoid its use on export-bound fruit.
More broadly, many crop protection products have MRL restrictions in key export markets. Growers are encouraged to review current export guidelines and verify MRL compliance before making pesticide applications. A reference spreadsheet outlining MRLs for commonly used pesticides across major citrus export markets, please consult this resource when making management decisions for export-bound fruit.
For additional information, please contact CCQC via email at jcranney@ccqc.org.