The traditional recommendation for controlling pests that kill or injure plants in home gardens is to protect plants by treating with insecticide. Gardeners and extension agents are often frustrated by the lack of reliable information about efficacy of non-chemical alternatives for pest management. Several pest management strategies are likely to be effective for these pests, but these strategies have not been tested in controlled experiments. This project focused on cultural control of common pests of green beans. We are evaluating the effects of repellents, made from garlic and from hot peppers, on feeding by bean leaf beetle and Mexican bean beetle. This is the second year for this experiment. We used the concentrations of garlic spray and pepper spray that appeared to be effective from last years data. These treatments are being compared to a control with no treatments and a control with insecticide dust. The experiment was performed at the Lane Avenue Horticulture Farm. Statistical analysis of the 1995 data is still being performed.
Within the field of vegetable pest research, strategies for non-chemical control are understudied compared to chemical control, and strategies appropriate to home gardens have been understudied compared with strategies for use on commercial vegetable farms. Gardening publications often make general recommendations about mechanical and cultural controls, but without data from controlled experiments to document efficacy of such controls.
We tried to find strategies that would be useful for managing pests on green beans. The target pests, based on observations of last years plots, were bean leaf beetle and Mexican bean beetle. These were the most frequently observed, and did the most damage, on last years plots.
There are two products currently on the market made from garlic and hot peppers. It is important to find out if they really are effective in preventing feeding. There seems to be great interest among gardeners about the efficacy of homemade repellents such as sprays of garlic or ground chili peppers.
The objective of this project was to evaluate the effectiveness of repellents on pests that attack green beans.
1) main plot
a) crop: green beans
b) pests: bean leaf beetle, Mexican bean beetle
c) planting dates: June 1
2) treatments:
a) no treatment
b) standard insecticide dust
c) tap water spray
d) garlic repellent spray
e) chili pepper repellent spray
f) row covers
B. Experimental design:
1) Each plot contained four replications. Each replication contained thirteen
treatment areas. Replications consisted of four rows of beans, with three feet
between treatments and ten feet between replications. Samples were drawn from
the middle rows of each treatment area.
C. Results:
1) Produce was harvested at appropriate times with a record of number, weight and
quality of beans. Foliage was evaluated for degree of damage, and dry weight for
each treatment was measured.
2) Results will be shared with extension agents via the Consumer Hort Newsletter, and with Master Gardeners via the Master Gardener Newsletter.
3) Information will be incorporated into new versions of Extension Factsheets.
Click here for harvest results.Harvest Results
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