The California Department of Pesticide Regulation (DPR) recently issued a letter to counties throughout Northern California that there is a need for emergency aerial applications of fungicides to orchards with standing water. Counties affected include Butte, Colusa, Glenn, Merced, San Joaquin, Stanislaus, Sutter, Tehama, Yolo and Yuba.

DPR notes that the unusual wet weather throughout the Sacramento Valley has made ground applications difficult and significant economic crop losses are expected if these aerial applications are not made. DPR is authorizing the emergency application of several fungicides to orchards with standing water only. The order will be in effect until June 1, 2017.

Products containing one or more of the following fungicide active ingredients may be applied to orchards with standing water: alumino tris (o-ethyl phosphonate), azoxystrobin, calcium polysulfide, captan, chlorothalonil, copper, copper oxychloride, copper hydroxide, cyprodinil, difenoconazole, iprodione, fenbuconazole, fenhexamid, fluopyram, mancozeb, metalaxyl, myclobutanil, propiconazole, pyrimethanil, tebuconazole, thiophanate-methyl, trifloxystrobin and the combination of boscalid and pyraclostrobin (trade name Pristine) and the combination of pyraclostrobin and fluxapyroxad (trade name Merivon). The key issue to be aware of when considering these applications is that any of the standing water cannot be pumped offsite, or flow offsite due to run-off.

The conditions for application are:

1. Water must be standing and will not flow into state waterways where fish and wildlife are likely to be affected. Applications are not allowed if water is flowing off the intended application site.
2. Standing water will not be pumped from the orchard after the fungicide application.
3. Applications are made in accordance with all other label directions.

Additionally, you cannot do an application if:

1. Soil moisture is at field capacity and a storm event, forecasted by the NOAA or NWS, is to occur within 48 hours following the application, or
2. A storm event that is likely to produce runoff is forecasted to occur within 48 hours following the application.

It is advisable that you read the full order and contact your county ag commissioner prior to any emergency application of fungicides.

For questions, contact Hank Giclas at (949) 885-2205.