Can an Apple Protection Bag Replace Pesticide Sprays?

An apple protection bag is a fabric or plastic sheet that is placed over young apples to protect them from insects and fungal pathogens. It is a relatively inexpensive and low-maintenance way to help protect young fruit from damage by insect pests and diseases.

The idea for bagging apples was originated in Japan, where farmers would place a cloth bag over each apple to protect them from coddling moths and stink bugs before the apples were picked. Japanese researchers have since reported that bags can reduce the incidence of pests and diseases, such as cork spot (a physiological disease), sooty blotch and flyspeck, which are fungal diseases.

Despite the widespread use of bagging in orchards, little is known about the efficacy of this technique for small-scale apple production. To determine if an apple protection bag could be used as a replacement for pesticide sprays, a field trial was conducted from 2013 to 2015 in a research apple orchard near Kearneysville, West Virginia.

A two-layer commercial bag, a paper bag (Target Corporation, Minneapolis, MN), and an untreated control were evaluated for their ability to protect fruit from pests and diseases. In each year of the study, a management program to control arthropod pests and diseases was implemented. Treatments were compared to control, and the effectiveness of each was determined by recording the number of damaged apples in each treatment.

Insect Pests

Stink bugs, flyspeck, and sooty blotch were the most common pests observed on fruit in both years of the study. These insects feed on fruit and cause damage to the skin and calyx. They also can affect the color of apples and may cause a brown, rusty appearance to them when they are ripe.

Insect damage was significantly lower in the commercial bag treatment than in the paper bag and untreated controls. However, the paper bag treatment was not as effective for controlling codling moth and plum curculio (an early season arthropod pest).

Fungicide Protection

A conventional pesticide management program (Imidan) was applied at the petal fall stage and again two weeks later to control plum curculio and codling moth in all years of the study. These treatments were followed by a dormant oil spray during the spring or winter.

Although the conventional pesticide management program did not provide significantly greater fruit protection from flyspeck and sooty blotch in 2015 than the paper bag treatment, the conventional pesticide program provided comparable fruit protection from San Jose scale (the most common disease found in all treatments). The damage caused by European apple sawfly and apple maggot was relatively minor during the study.

In addition to being a useful alternative to pesticide sprays, apple bags can also be used to improve the color of apples, prevent hail from damaging young fruit, and minimize pollution of pesticides by removing bags after harvest. However, it is important to remember that apple bagging should only be done as a last resort after other control measures have failed.