Development and Demonstration of Methods toward Sustainable Apple Production

1989 Annual Report for LNC89-022

Project Type: Research and Education
Funds awarded in 1989: $24,500.00
Projected End Date: 12/31/1991
Region: North Central
State: Michigan
Project Coordinator:
Stuart Gage
Michigan State University

Development and Demonstration of Methods toward Sustainable Apple Production


1) Develop a biological monitoring system for assessment of sustainable apple production with
cooperators in the Rodale Farm Network.
2) Evaluate plantings to enhance predatory insects and use animals to manage weeds and control
insects in fallen apples.
3) Evaluate alternative marketing strategies for low-input apple products.

Biological monitoring required two aspects: weather monitoring and observations on pest
occurrence and abundance. Automated weather stations were set up at the Double J Fruit Ranch
and the Kellogg orchards to collect specific weather data in the apple block selected for this
study. Monitoring was conducted on four apple insect pests: codling moth, plum curculio, apple
maggot, Japanese beetles; and on two beneficial insects: lacewings and ladybird beetles.
Location of all trees in each orchard were mapped to enable analysis of the spatial distribution of
insects and apple production. Visual and trap monitoring of these insects was correlated with
weather data to determine appropriate timing for biological controls.

Barred Rock chickens were introduced to the Kellogg orchard in 1990 and 1991 to evaluate their
effects on orchard pests, particularly plum curculio, Japanese beetles and weeds. On August 25,
1990, a survey was conducted to determine the response of consumers to the taste of Redfree
disease-resistant apples (from the Kellogg orchard), in fresh, juiced, or dried form, to assess the
potential marketability and consumer appeal of disease-resistant apples.

Mating disruption was chosen as the biological control method for codling moth at both orchard
sites. In both 1990 and 1991, fewer male codling moths were trapped in disrupted areas than in
non-disrupted areas of both orchards. In 1990, codling moth damage approximated 20 percent in
the disrupted area of Double J Fruit Ranch and 12 percent at the Kellogg orchard. During the
previous 1989 season, damage had been 80 percent in an unsprayed area at the Double J Fruit
Ranch and 40 percent at Kellogg. Due to a much warmer season and lower apple production
(frost damage) in 1991, however, both orchards had much higher damage in disrupted areas.
The Double J Fruit Ranch disrupted area had 50+ percent codling moth damage, while the
Kellogg disrupted area had 80+ percent. The disruption technique appears to provide a
significant degree of control during years with normal temperatures.

Throughout the 1990 season, it was apparent that the Kellogg orchard had a greater variety and
density of ladybird beetles and lacewings than did Double J Fruit Ranch, which was most likely
attributed to differences in surrounding habitat. At both orchards, lacewings were seen in greater
numbers and more continuously during the season than were any species of ladybird beetles.
This is an important observation for orchardists who wish to nurture predaceous insects, for
certain predators such as ladybird beetles have specific habitat preferences. Lacewings seem to
be less particular about food or habitat, and therefore may be more suitable as orchard predators
than ladybird beetles.

The chickens' aggressive foraging of weeds caused a dramatic reduction in the amount of
vegetation present underneath the trees in 1990. The chickens seemed to prefer succulent
broadleaf weeds, and showed an appetite for roots, which contributed to removal of grasses.
The blades of mature grasses were avoided, except the tips which the chickens nipped off,
apparently since they were the only tender part of the blade. It appears when introduced early in
the season (spring), chickens can reduce vegetation as effectively as an herbicide. During both
1990 and 1991, there were no conclusive chicken predation effects on codling moth populations.
However in 1990, there was approximately 25-30 percent less damage caused by plum curculio
in rows with chickens, compared to rows without chickens. In 1991, there was no significant
difference in plum curculio damage.

The results of the consumers survey revealed that consumers seemed to enjoy the Redfree
disease-resistant variety at least as well as the varieties they typically bought at the market.
Whether or not consumer demand would be bolstered by the disease-resistant trait is
questionable, since previous market surveys have shown that consumers in general respond to
taste and aesthetic appeal more than to reduced pesticide use. A second factor that growers must
consider with disease-resistant varieties are storage problems, since some varieties store poorly.
In such cases, marketing these as a early summer variety would be the most expedient avenue.
Continued research is improving and producing varieties with longer storage life.

Areas needing further study:
This project has demonstrated the remarkable ability of animals to aid in the management of
vegetation and pests within the orchard. However, more studies are necessary to determine
specific management techniques for incorporating livestock and poultry into orchard systems,
e.g. how to prevent tree damage from animals. Additionally, orchards have extensive idle area
that when not grazed, is mowed repeatedly during the season. Orchardists could increase the
return on their land by planting intercrops in these middles. However, there has not as yet been
an exhaustive study regarding which intercrops are compatible in temperate orchards, especially
as the trees mature.