APIS Volume 5, Number 1, January 1987
In this issue
- Considerations When Moving to Citrus: Canker and Aldicarb
CITRUS HONEY CONSIDERATIONS
This is the time of year when the sap begins to rise in the Florida beekeeper. The Ides of March are not far off when citrus traditionally blooms. Soon each will have to make a decision whether to "go to the orange," or sit the season out on the sidelines. And in recent years it has become more and more risky. Beyond the traditional things (rain, wind, cold weather) that can effect prospects of a good citrus nectar flow, the spectres of freezes that have decimated so many acres and citrus canker (See November 1984 APIS) which can and has limited access to groves have appeared.
Regional considerations are also important. Although citrus plantings continue to increase southward from the Central Florida Ridge, often the soils and conditions under which the trees are growing, as well as varieties of trees, can be very different than those beekeepers might be used to. Can these influence a nectar crop? Nobody knows for sure, but experiences by some suggest that plantings in south Florida on less well drained soils do not provide the nectar crops expected on the Central Florida Ridge. Agricultural pursuits have been dictated by soil types for centuries; should it be any different in Florida citrus? Certainly this is true for the wild bee forage.
More recently, the use of Temik® (aldicarb) has become more a concern for beekeepers in citrus groves. Aldicarb is a nematicide and systemic insecticide which some believe also acts as a powerful growth stimulator. It is usually disked into the soil and when activated by water, can kill nematodes in the soil and is conducted through the plants vascular system. When insects feed on the leaves, they can be affected by the material. See June 1986 APIS.
If this is the case, what about potential effects of honey bees foraging on nectar? There is no clear answer. The material is not applied in all groves nor is it important in culturing all citrus varieties, its movement through trees is not well understood, and the type of soil in which the tree is growing can dramatically effect uptake and ultimate toxicity of the material. Half life (the time it takes for toxicity to degrade by one-half) can vary between 14 to as much as 78 days, depending on microbial action in the soil. The parent material also breaks down into two components that are also toxic but to varying degrees.
Further complicating the issue is that bees feeding on nectar contaminated by aldicarb may be able to detoxify it to a degree. Experience in groves has not indicated classic pesticide kill by aldicarb; no colonies have actually been destroyed. More likely contaminated nectar present in chronic low dosages could weaken a colony and/or affect its reproductive ability. Both conditions have bee substantiated for other pesticides.
Reports in Florida by beekeepers concerning aldicarb's effects are extremely variable and none have been scientifically verified. This does not mean, however, the material is not in the honey bees' environment. As I reported in the June 1996 issue of this newsletter, it has been found in Florida nectar samples for the first time. Research in both California and Washington indicates aldicarb in nectar effects colonies. Unfortunately, we have no way to correlate research done on the west coast with Florida conditions.
This all boils down a classic case of "let the beekeeper beware." There are several things that can be done. Correlate nectar and honey crops with where the pesticide might have been applied, and ask growers and managers if they use the material and where. Try to find out when it was applied and when activated by water (rainfall or irrigation). Also inquire of other beekeepers in the area about their experiences in recent times. Reports indicate severe problems have only occurred in the last five years or so. In other words, as with any other management decision, get all the facts before committing your bees to certain citrus locations.
A final word of caution. Communicate and cooperate with grove owners and managers on this issue. Most are willing to provide basic information on their practices. Be careful concerning treatment of the aldicarb issue. Experience suggests that growers are not convinced the material does damage to colonies and may not stop using the product even if proof did exist. This material means a lot to many citrus grove owners and managers. At a recent meeting on the subject, one grower stated, "...it has put $50,000 dollars pure profit in my pocket." This is a strong argument to use the material, especially in conjunction with published studies of its effectiveness. Especially vociferous beekeepers who have spoken against Temik® application have been denied access to citrus groves. A word to the wise should be sufficient. For more on the Citrus-Beekeeper relationship see the April 1986 APIS.
[Editor's Note 5/12/1997--This issue has died down considerably. Temik® has been under the gun for a good many years and is always a controversial issue durng the reregistration process. The active material, aldicarb, has not caused recent problems in citrus orchards.]
Sincerely,
Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (352) 392-1801, Ext. 143 FAX: (352)-392-0190
http://www.ifas.ufl.edu/~mts/apishtm/apis.htm
INTERNET Address: MTS@GNV.IFAS.UFL.EDU
©1987 M.T. Sanford "All Rights Reserved
