By David Campbell and Danielle Treadwell
Peach growers have rediscovered a tool to add to their integrated pest and disease management toolbox — a unique paper bag. Easy to install and remove, the bag has extra durability to withstand wind and rain throughout the season. And if our data is consistent with previous observations, bagging may be affordable for many operations.
Bagging is currently used to protect apples, pears and loquats in the United States, Spain, Japan and China (R.R. Sharma, 2014). Globally, bagging reduces damage for multiple crop-pest complexes. Bagging has been shown to reduce pomegranate injury caused by anar butterfly larval feeding in India (B.G. Bagle, 2011) as well as reduce anthracnose and stem end rot diseases for mango in Australia (P.J. Hofman et al., 1997). Although bagging generally increases yield, some other fruit quality characteristics, including percent of soluble solids and acidity, have shown mixed results (R.R. Sharma, 2014).
A multi-state research team including horticulturalists, economists and pest management experts from Florida, Georgia and South Carolina are investigating the practicality and efficacy of bagging for peach growers in the Southeast. Preliminary findings indicate that bagging can protect peaches from insect feeding and pathogenic fungal injury.
HOW AND WHEN BAGS ARE USED
Peach fruitlets are bagged after they are thinned to an appropriate density and receive a protective antifungal spray. The bag is placed over the fruitlet when it is approximately 1 inch long and fits snugly around the branch. The sides of the bag are folded in an accordion-like fashion, and the bag is secured with a metal twist tie that is built into the bag.
Approximately seven to 10 days before harvest, the bag is removed to increase the red color in the peach skin. Fruit is manually harvested as usual. After the metal twist tie is removed, the bag can be recycled after harvest depending on local recycling requirements.
In Florida, bagging can begin as early as February, but will occur later for cultivars that require more chill hours to set fruit. Producers in Georgia and South Carolina typically bag fruit in March and April, respectively.
LABOR AND COSTS
In Florida, members of the research team installed an average of 2.5 bags per minute and removed 48 bags per minute. Depending on the size of the operation, bagging can require an extensive labor force. The choice to bag may depend on the grower’s market. Depending on the quantity purchased, bags cost about 1 cent each.
For an acre of Florida peach trees planted to a density of 117 trees per acre that yielded 150 fruit/tree, the cost of bagging would equal approximately $1,592, based on the bag price plus $12 per hour for labor. An estimated 123 hours of total labor is needed for bagging installation and removal. Additional research is necessary to determine if bagged peaches can be sold at a price premium or if current management practices could change, such as a reduced spray schedule, to offset the price of bagging.
For organic or conventional producers who experience a significant loss in yield due to pests and diseases, bagging may provide the tool needed to improve fruit quality and increase yield. Bags are currently commercially available. Any producer in the Southeast interested in testing this technology can contact the authors of this article for more information.
Acknowledgment: This article was developed in part with funding from the U.S. Department of Agriculture’s Organic Agriculture Research and Extension Initiative Project Number 2016-51300-25726.
David Campbell is a doctoral student and Danielle Treadwell is an associate professor at the University of Florida in Gainesville.
This article was featured in the April issue of VSCNews magazine. To receive future issues of VSCNews magazine, click here.
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