Editor: Jeff Williamson (Professor, Horticultural Science Department, IFAS, University of Florida)

Officers: Jerry Mixon, Jr. (president), Dean Deihl (vice president), Sheri Brothers (secretary and treasurer), Jeff Williamson (educational program director and newsletter editor).

Board of Directors: Jerry Mixon, Jr., Dean Deihl, Ken Patterson, Jimmy Miller, Gerald Mixon, Bob Payne, Steve Blount and Paul Lyrene.

Happy holidays to you and your families!This is our final newsletter for 2001 so I wanted to review some of the developments in Florida blueberries over the past year.

First, congratulations to our "northern" neighbors in Georgia with the forming of their new Georgia Blueberry Grower’s Association. Next, congratulations to all Florida blueberry growers for our record setting year. Per USDA, we shipped in our Florida window 2.3 million pounds of fresh blueberries.

We were made aware of several new "pests" -- gall midges and thrips. Although their presence in Florida is not new per se, the information concerning their importance and negative impact to the Florida blueberry harvest numbers and how to combat them is new.

We have been made aware of increasing potential for more encroachment to our market window both here at home (USA) and abroad. In addition, we have lost Benlate, one of our key weapons in battling certain fungal diseases in blueberries.

Who could recap our year without mentioning the horror of September 11? The impact of these tragedies on our personal lives as well as our business of growing blueberries is still being determined. One of the potential results of September 11, 2001 will be decreased funding for University of Florida Extension programs including those with blueberries. We will be asked as an Association to assist with increased funding for research projects that Jeff and others are and will be working on. How will we accomplish this? The most effective way will be through increased participation in the Association. We need to step up our efforts in membership recruiting and participate in active fund raising opportunities such as the purchase of FBGA shirts (ten dollars per shirt goes to the Association) and raffle tickets at FBGA meetings. There will be a new and exciting fund raising opportunity at the spring meeting.

If we can do these things we should not see a drop off in the things being done on our behalf regarding research and extension in blueberry production.

In conclusion, let’s be on our toes in cold/frost protection and do all we can as growers to produce the finest quality blueberries, not only in Florida but throughout the world, and our future should continue to be bright.

Finally, my prayer for you and yours is to have a safe and blessed holiday season and that the Lord would bless our efforts in the coming season.

Meet Bob Payne: Featured Blueberry Grower

Payne’s blueberry farm is located in Sebring, Florida which means we receive a lot less chill hours than our north Florida friends. The varieties that we grow are mainly ‘Sharpblue’, ‘Sapphire’, and numerous test selections. We do not use pine bark because of its high cost and because our soil is between 1 and 3 % organic matter. We currently plant on a 3 by 9 foot spacing, or 1600 plants per acre. We are working with Dr. Paul Lyrene to find some new varieties that will work in central Florida. Dr. Paul will evaluate the fruit of the first planting this year and hopefully, there might be something promising in the years to come.

Something we have done on our farm that has helped control the deer is to build a fence. We have used woven wire on the bottom four feet and strung seven strands of barb wire above the woven wire to discourage the deer from jumping over. The total height of the fence is about eight feet. The posts are 20 feet apart with every other one being a 10 foot post. The other posts are the standard 6.5 feet long. The barb wire should be of the gaucho type with barbs every four inches. This has worked pretty well for us during the past 10 or so years. The woven wire keeps the does from teaching the fawns that the blueberries are a good food source and after a few years the new generations do not realize what they are missing. The deer will try to go through the strands a few times but the gaucho really persuades them that there is a better source of food than our berry farm. This is not 100 % effective for the first couple of years and when deer get in if a dog chases them, they will get the message. This has been the most cost effective project that we have done to increase yields on our farm.

by Jeff Williamson

Dormex (hydrogen cyanamide) is a plant growth regulator that became available for commercial use in Florida blueberries last year. To date, our experiments, and grower experience, have shown Dormex to be a useful tool for stimulating earlier and stronger spring leafing of several southern highbush (and Climax rabbiteye) cultivars in Florida. Where spring leafing has been significantly advanced by Dormex, berries were often harvested earlier than would otherwise be possible. Increased average berry weight (size) and a slight increase in total yield have also been noted in some cases but the main advantage seems to be increased earliness. Most of our research has been conducted with the cultivar ‘Misty’. Increased vegetative budbreak and earlier ripening from Dormex have been demonstrated under a range of environmental and climatic conditions during several seasons in Florida for the variety ‘Misty’. On other cultivars, growers have reported similar though perhaps less dramatic results. Grower reports also indicate Dormex may be effective at concentrating bloom which could improve fruit set and result in a more concentrated harvest season. The Dormex label for Florida warns against applying Dormex to ‘Sharpblue’. ‘Sharpblue’ flower buds appear to be more susceptible to injury (spray burn) from Dormex than are flower buds of most other cultivars. Sharpblue is inherently a strong spring leafing cultivar, so it may not benefit from the "Dormex response" as much as some other cultivars. More research and experience are needed to determine if Dormex can be safely applied to the numerous blueberry cultivars currently grown in Florida. Thus far our research has shown that Dormex can be applied to ‘Misty’, ‘Star’, ‘Southmoon’, ‘Gulf Coast’ and ‘Climax’ with minimal (acceptable) levels of flower bud injury.

What rate of Dormex should be used? If misapplied, Dormex has the potential to damage flower buds. Therefore, it is very important that growers follow the label directions exactly. The Florida label calls for up to 1.5% (v/v) Dormex in 50 to 100 gallons of spray per acre using up to 0.5% (v/v) of one of the nonionic surfactants, Latron B1956 or Agri-Dex. Higher Dormex spray concentrations have resulted in significant flower bud thinning in all of our experiments and have reduced total yields. Dormex applied at 1.5 % (v/v) has consistently shown increased leafing and earlier fruit ripening of ‘Misty’ without significant flower bud thinning. Dormex applied at 1.5 % (v/v) has actually increased total yields in some cases. This is probably a result of increased average fruit size combined with minimal, if any, fruit thinning. The effect of Dormex is very localized on plants. Therefore thorough coverage is essential.

When should Dormex be applied? The Florida label calls for applications to be made 30 or more days prior to natural budbreak. It appears that Dormex is most effective when applied to dormant plants after significant winter chilling has occurred and about 30 days prior to natural budbreak. Although the calendar should not be used to time Dormex spray applications, in Alachua County, late December is usually about 30 to 40 days before flowering for most cultivars grown there. During the last 2 to 3 years, applications of Dormex made in Alachua County between about December 20 and January 3 have usually increased vegetative budbreak and advanced fruit harvest of responsive cultivars. During "normal" winters thus far, differences within this time frame in Alachua County have not been significant. Of course the onset of dormancy, chill accumulation, and the timing of natural budbreak will vary from year to year and from one location to another in Florida. Hence, the timing of Dormex applications should be based on the weather and anticipated date of natural budbreak, not the calendar date.

Application of Dormex to plants that have received little or no chilling resulted in less efficacy and more injury to stems and flower buds emphasizing the importance of restricting application of Dormex to the dormant period when some chilling is likely to have occurred, but before flower bud swell has progressed past stage 2 (that is before flower bud scales begin to separate). Delaying application until, or just prior to, the beginning of flowering (usually mid- to late January in Alachua County) has resulted in serious flower bud thinning and yield reduction. The application time for maximum benefit will depend on the winter weather and location of the site.

What Cultivars Benefit From Dormex? This is a very important question but one for which we do not have enough data to answer completely. Our field experiments, and the 1999 Florida E.U.P. Program, evaluated Dormex when applied to the following cultivars - ‘Misty’, ‘Climax’, ‘Gulf Coast’, ‘Star’ and ‘Southmoon’. No significant flower bud injury was observed for any of these cultivars when Dormex was applied at rates of between 1.0 and 2.0 % (v/v) to dormant plants during late December through early January in north-central Florida. In all cases, vegetative budbreak and leafing were advanced, and in most situations, harvest date was advanced and berry quality was improved. However, that is not to say that all cultivars respond equally to treatment with Dormex. The cultivars which appear to respond best to Dormex are those cultivars that leaf poorly in the spring such as ‘Misty’.

The cultivar ‘Sharpblue’ has shown a higher than usual sensitivity to Dormex resulting in flower bud injury and fruit thinning which has sometimes reduced yields. ‘Sharpblue’ flowers tend to be more swollen and have slightly more open bud scales during the winter than other blueberry cultivars grown in Florida and this difference in development and flower bud structure may account for its increased sensitivity to Dormex.

In summary, the potential benefits from Dormex when used correctly include strong spring budbreak and vegetative growth, shorter fruit development periods with earlier harvest periods, increased average fruit weight (size), and slight increases in total yield. It is possible that the concentrated bloom and harvest periods and shortened fruit development periods obtained with Dormex could help with disease and insect control and potentially reduce the number of annual pesticide applications needed in Florida blueberries.

On the other hand, when applied incorrectly, Dormex can result in flower bud injury, excessive fruit thinning and yield reductions. Also, potential users should be aware that Dormex is classified as a restricted use pesticide. Extreme caution should be used when handling and applying this material and ALL LABEL DIRECTIONS SHOULD FOLLOWED EXACTLY.

Dormex orders for Florida have already been placed for this winter. If you have any questions about where or when to pick up your order, contact Rick Hill at (813) 781-0902.