The California Citrus Quality Council (CCQC) is providing the following clarifying information to the industry about the Korea and China protocols.
The China protocol specifically requires a copper application for the first application. Making a copper application as the first application will provide the greatest flexibility for qualifying acreage for China or Korea. If you are sure that you will not be shipping to China, the first application can be a non-copper alternative.
For Septoriaand Phytophthora control, U.C. Riverside’s Dr. Jim Adaskaveg recommends use of a Zinc-Copper-Lime or Zinc-Copper-Bordeaux mixture for the best result. However, please note that the use of zinc or lime are not required to meet the protocol.
According to Adaskaveg, agricultural lime is mixed with copper sulfate (Bordeaux mixture) or with fixed coppers (copper hydroxide or copper oxide) to increase the persistence, reduce the potential of copper injury, and to control leaf hoppers. Zinc sulfate is often added. Alternatives, however, include Abound, Quadris Top, Priaxor, Luna Sensation, and Ph-D or Oso.
Agricultural lime is calcium carbonate or crushed limestone whereas hydrated lime (builders lime) is calcium hydroxide. Hydrated lime is generally not used because it is more expensive. An alternative is to use a fixed copper (Champ, Kocide, NuCop, etc.) with a sticker adjuvant such as NuFilm-P, -17, Cohere, etc. This increases persistence but does not provide the other benefit of leaf hopper control. Apparently, the lime is a repellent to leaf hoppers. The alternative fungicides listed above are also applied with stickers.
If lime is not used and zinc sulfate is mixed in the spray tank with a fixed copper and sticker to address zinc deficiencies in the citrus trees to be treated, be sure to buffer the spray solution. Zinc sulfate will acidify the tank and potentially cause phytotoxicity. Consult a PCA if zinc sulfate is used with the fixed copper and sticker.
If agricultural spray oils are used as a sticker, a summer oil (e.g., 415) is preferred but a dormant oil (e.g., 440) can be used. Use a low suggested rate (0.5-1%). Oil applications will darken the tree and phytotoxicity may occur as sun burn especially on southern end trees or southern rows exposed to more sunlight. Be sure to turn off sprayers between rows. Keeping them on will cause an excessive rate of oil to be applied to end trees of each row.
If the fruit is expected to be shipped to China and Korea then you must use copper as the first application. Copper-lime (zinc) mixtures or a fixed copper and a sticker can be used and the fruit would be eligible for both markets. The China protocol makes the first copper application mandatory. Alternatives to copper can be used for the second or third application if needed based on the disease forecasts for the China program. Alternatives include Orondis, Revus, and Orondis Ultra (a mixture of the two).
Please contact CCQC President Jim Cranney by telephone at (530) 885-1894 or via e-mail at jcranney@ccqc.org for further information.
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