A Florida-specific Peach Spray Guide??

October, 2010

I recently returned from the Southeast Professional Fruit Workers Conference held in Asheville, NC last week, and it was beautiful!  There were many great presentations on peach and apple disease management, fruit antioxidant chemistry, postharvest applications to prolong apple shelf life, grapevine evaluations, and apple thinning using a carbon balance approach.

One the major tasks during this conference is to make changes to the regional tree fruit spray guide (http://www.ent.uga.edu/peach/PeachGuide.pdf).  One thing that became clear to me as I brought up several different topics that are specific to Florida growers is that attempting to author a regional spray guide is very difficult.  At least one state has authored their own spray guide for peaches and stone fruit, North Carolina, while other states in the Southeast simply use the regional guide as their go-to resource.

Bacterial Spot on Peach Fruit
Figure 1. Bacterial spot on peach fruit. (Courtesy of forestryimages.org)

In northern states that have significant peach production, a major emphasis  is on preharvest control, specifically brown rot and bacterial spot management.  Of course, these growing areas have a later bloom date, and extended ripening season, with varieties that have longer fruit developmental periods.  Thus, fruit are ripening during prime infection periods for brown rot and significant efforts are made to apply various fungicides to combat this disease.

Many of the varieties developed at the University of Florida in the past 20 years have excellent resistance to bacterial spot (Xanthomonas compestris pv. pruni (Sm.) Young et al.; Figure 1, 2), and thus this particular disease only really affects early varieties TropicBeauty and FloridaPrince.  One grower that I spoke to this year had bacterial spot symptoms show up with a heavy crop load, with no applications for bacterial spot in TropicBeauty.  However, newer non-melting flesh varieties such as UFSun, UFOne, UFGold, etc. have excellent bacterial spot resistance.

Figure 2. Bacterial spot leaf symptoms in peach. Courtesy of forestryimages.org

These are just a few examples of diseases that have significant coverage in the Southeastern Peach, Nectarine, and Plum Pest Management and Culture Guide that growers in Florida do not routinely have to control.

We are thinking of authoring a new Florida Stone Fruit Pest Management Guide that focuses on postharvest management of diseases, and contains information on subtropical pests and diseases (such as  Caribbean Fruit Fly, Mediterranean Fruit Fly, etc.).   What do you think?


Mercy Olmstead, Ph.D.