April, 2009       

VOL. 23, NO. 4                                                                             

IN THIS ISSUE:

MORE GREENING IN LOUISIANA
TCM MEETING
GREENING AND TEXAS NURSERIES
TDA OPERATIONS
NEW PESTICIDES, LABELING OR NAMES

MORE GREENING IN LOUISIANA            

It was to be expected but still not what anyone west of Florida wanted to hear: Two additional cases of Asian citrus greening were confirmed in Louisiana during March. The first was an orange tree in Bogalusa, Washington Parish; the second was an orange tree in New Orleans. Both discoveries occurred in the same two parishes as the previous three finds, bringing the total in Bogalusa to three trees confirmed, and in New Orleans to two confirmed cases. To the best of my knowledge, the psyllid has not yet been confirmed in Washington Parish, yet three trees have been diagnosed with greening.

The time between the first finds and the most recent two confirmations should ring a warning bell to all citrus tree owners in Texas, homeowner and commercial. This disease is so insidious because of its latency (time between inoculation and the appearance of visible symptoms of the bacterium) that we simply cannot take it for granted and assume that it is not already somewhere in western Louisiana or even in Texas.

TCM MEETING

The Mid-Winter meeting of Texas Citrus Mutual at the TAMU-K Citrus Center was rather well attended. Most of the presentations dealt with pest problems of one sort or another. Of special interest was an interesting talk by Nate Jamison, a citrus nurseryman from Florida. It seems that Mr. Jamison was a member of the ad hoc committee put together in Florida following the discovery of citrus greening in 2005 to come up with the best plan of action they could for all facets of the industry to follow in response to the occurrence of greening. The efforts of this committee set the stage for the way citrus nurseries in Florida must now grow their foundation trees, increase blocks and nursery trees, i.e., in insect-resistant structures.

GREENING AND TEXAS NURSERIES

I know the way many of our Texas nurserymen view the idea of growing in enclosed structures--they don't think they can grow as large or as good a tree as they can outdoors in the ground, and even if they could, the cost of the structures is considered too prohibitive to consider. Granted, there have been some disappointing results from shadehouse production in containers. Nonetheless, given the funds to build the structures, the growing problems can be overcome.

Of the greatest urgency at the moment, however, is the necessity of finding the funding to put our increase block and foundation block under insect-resistant structures. Presently, our total land area is about seven acres in size, mainly due to the rather wide spacing of the trees in the foundation block. We may have to consider another, smaller, foundation block with closer spacings so as to reduce the overall cost of protecting our supply of certified budwood, while still being able to verify horticultural characteristics of the source trees.

Until our budwood trees are protected, I can see no consensus regarding enclosing commercial nurseries. Indeed, it is likely that no such concensus will occur until greening is confirmed in the state--at which time we will be no better off than Florida was in that we'll be trying to "lock the barn after the horse got out".

Back to the insect-resistant structure, there are some very decided advantages that should be considered. For example, the structure would exclude leafminer, aphids (including the brown citrus aphid vector of severe strains of citrus tristeza), and almost all insect pests, several diseases and almost all weed seeds (a major concern in container production). Mites, however, can become problematic. With the exception of mite controls, you're looking at a pretty "green" operation with a big savings in pesticides and application costs.

TDA OPERATIONS

Last month I reported on a joint action of TDA and USDA-APHIS-PPQ-SITC (the latter acronym stands for Smuggling Interdiction and Trade Compliance). At a meeting last week, I was provided a copy of what TDA has been doing related to citrus in their Region 5--the 19 county area of South Texas from Refugio County to Webb County and south.

In the category of Market Blitz Inspections, which includes retail outlets, flea markets and other places where citrus plants are sold, TDA inspectors made 58 inspections in FY 2008. Of the 15 which failed, 12 had citrus regulation violations, three of which involved citrus plants that were illegally shipped into the Citrus Production Zone. The other nine citrus violations were violations of the citrus labeling requirement. Because two of those locations had unlabeled citrus trees for which inspectors could not determine the origin, those trees were seized and destroyed.

In the first six months of FY 2009, 34 inspections turned up five failures due to citrus violations--two for violation of the labeling requirement and three violations for having been illegally shipped into the Citrus Production Zone.

TDA also worked jointly with SITC for a couple of weeks last summer, checking 36 locations. Eleven of those locations had quarantine violations, of which seven involved citrus.

They are pursuing leads about unlicensed citrus nurseries, citrus labeling violations or of Asian citrus psyllid infestations. These leads came primarily from inspectors employed by Texas Citrus Mutual (but they will respond to a good lead from anybody); several violations were found as a consequence of the followup.

Finally, the put in a lot of manhours to operate four 72-hour road stations coming into the area during the last 18 months. No citrus violations were encountered at these road station checks.

I don't intend to criticize the latter effort, but I would point out that among the Market Blitz Inspections, six of the 17 citrus violations over the last 18 months were for trees being shipped into the Citrus Production Zone. Obviously, these six violations did not come into the Citrus Production Zone during the times of operation of the temporary road stations. The argument could be made that not enough three-day road station operations were staged, but those are expensive operations, especially with regard to manpower. I wonder if the same number of man hours (about 2400) might not be more effective if they were split into 6 or 8 hour shifts which would be operated far more often.

NEW PESTICIDES, LABELING OR NAMES

Dow-Agro Sciences has one new product and a new formulation of an old standby. Delegate is an insecticide that controls psyllids--nymphs, adults and eggs--and other pests. Applied at low rates with oil, it has a four hour re-intry, one day preharvest interval, and it has three to five weeks residual activity.

Lorsban Advance will replace the well-known Lorsban 4E. The apparent major advantage of this new formulation is its low odor, somewhat akin to the long dead Dursban LO that so many home gardeners really loved. There is a supplemental label for use with oil.

While not new, Imidan 70W from Gowan is a product that provides control of root weevils and psyllids. What is new is that it now has a 24C label for use in Texas citrus.

MANA is an Israeli company with US headquarters in Raleigh, NC. It is presently offering generic formulations of several pesticides that are familiar to the Texas citrus industry. MANA stands for Makhteshim Agan of North America, which might be a little harder to get one's tongue around than the acronym.

  
JULIAN W. SAULS, Ph.D.
Professor & Extension Horticulturist
2401 East Highway 83
Weslaco TX 78596