Sugar Spray Experiment- Cabbage

Please read the entire protocol before you start.

Purpose: Determine if sprays of sugar-water are effective in controlling cabbage worms.

Overview:

• Do not use any pesticide on the cabbage plants, whether against cabbage worms or any other cabbage insect.
• Do not use overhead irrigation within 3 days of applying the sugar-water.
• Feel free to add compost, manure or a start-up fertilizer to the soil prior to planting.
• Irrigate so plants get a minimum of 1 inch of water each week.
• Keep plots free of weeds. You can mulch, hoe, or manually pull weeds if needed.
• Information to be recorded: insect counts and yield.
• Continue to record the observations even though you think the experiment may have failed.

Materials Needed:

- 1 lb of sugar

- Water

- 10 cabbage seedlings

- A clean sprayer

Time Line:

Week 1 - Transplant cabbage seedlings.

Week 2 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 3 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 4 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 5 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 6 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 7 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 8 - Apply water and sugar-water solution.

- Record insect counts 15 minutes and 24 hours after application of solutions.

Week 9 - Make final insect count.

- Record yields.

Planting

· Plant two plots of 6 cabbage seedlings each, 2 feet apart (in one or more rows) on or before May 20.

· Separate plots by at least 15 feet.

· Use Golden Acre cabbage that you grow or purchase as seedlings from your local garden center. All plants should be the same variety.

Applying the Sugar Water Treatment

• Flip a coin to choose which plot will receive sugar-water treatment and which plot will be sprayed with water during the season.
• Spray the plot receiving water before spraying the plot receiving sugar-water.
• Water Treatment: Spray plants with one quart of tap water. Coat plants and soil of plot with water. Use the entire quart of water.
• Sugar-Water Treatment: For each application of sugar-water, dissolve 6 tablespoons of sugar in a quart of water. Spray plants in the sugar spray treatment plot until the entire quart is emptied. This spray will coat plants and the plot soil surface with sugar-water.
• Rinse sprayer thoroughly before storing.

Information to be Collected

• Record planting date and cabbage variety.
• Apply fresh water and sugar-water solutions every week during the growing season.
• Count the number of caterpillar greater than 1/2" long (the diameter of a dime) and the number of caterpillars less than 1/2" long on each plant in both plots 15 minutes after spraying.
• Count the number of parasitized pupae or worms with cocoons 15 minutes after spraying <www.nysaes.cornell.edu/ent/biocontrol/parasitoids/cotesia.html>

<www.nysaes.cornell.edu/ent/biocontrol/parasitoids/diadegma.html>

• Also count the number of ants, stinging wasps (yellow jackets and hornets), and lady beetles you see on each plant 15 minutes and 24 hours after spraying.
• Make one final count of insects 9 weeks after transplanting.
• Record yields in each plot 9 weeks after transplanting. Harvest all plants on the same day (9 weeks after transplanting). Remove the wrapper leaves and wrap a measuring tape around the cabbage head to measure its circumference (in inches) at its widest point. Record circumference of each cabbage. Rate the quality of each head.
• If the cabbage heads are not yet ready to be harvested at 9 weeks, you do not need to harvest them. However, you must measure the circumference of each head at its widest point. Record circumference of each cabbage. Rate the quality of each head.

Time Saver: There is no need to spend more than 5 minutes counting the insects on each plant.

Note: You may wish to have the gardeners conduct a shorter version of this experiment. The gardeners can spray the sugar-water and make observations without having to count the insects. At week 9, they could grade the cabbage in terms of quality.