Each year I get several calls from gardeners wondering why their cucumbers are not producing fruit when they see plenty of flowers. Cucumber flowers are either male or female. The richer and more balanced your soil, the more female flowers you will have. This is yet another good reason to test your soil fertility. It is not just the nutrient content of your soil that matters. Our Hamilton County soils tend to be alkaline. If the pH is too high, the nutrients in the soil may not be available to the plant. Soil fertility test kits can be obtained from our office or you can order online at: http://www.hcswcd.org/soil-fertility.html
Another factor we deal with in our county is soil compaction. Once soil pore space gets below 25%, it is difficult to grow anything!
A solution is to add more organic material to your soil prior to conducting a soil fertility test.
Cucumber beetles are a primary nemesis to cucumber plants. In North American cucurbit crops, two species of cucumber beetle present the most problems. These are the striped cucumber beetle (Aclymma vittatum in the eastern U.S. and A. trivittatum in the west) and the spotted cucumber beetle (Diabrotica undecimpunctata). Adults of the two species are easy to tell apart: the spotted cucumber beetle is somewhat larger and has dark black spots whereas the striped cucumber beetle has long black stripes down its back.
Cucumber beetles damage cucurbit crops in at least three ways.
1. Their feeding directly stunts plants and, when flowers are eaten, can reduce fruit set.
2. Cucumber beetles transmit bacterial wilt disease (Erwinia tracheiphila). More information on bacterial wilt can be found in this APSNet article on Bacterial Wilt and this Cornell Vegetable MD Online fact sheet on Cucumber Beetles, Corn Rootworms and Bacterial Wilt in Cucurbits.
3. Adults scar the fruit reducing its marketability.
Keeping Beatles Away.
1. Floating row covers left in place until flowering begins provides the most reliable defense against cucumber beetles.
2. Straw mulch can help reduce cucumber beetle problems in at least 3 different ways. First, mulch might directly slow beetle movement from one plant to another (Cranshaw, 1998; Olkowski, 2000). Second, the mulch provides refuge for wolf spiders and other predators from hot and dry conditions, helping predator conservation (Snyder and Wise, 2001; Williams and Wise, 2003). Third, the straw mulch is food for springtails and other insects that eat decaying plant material; these decomposers are important non-pest prey for spiders, helping to further build spider numbers (Halaj and Wise, 2002). It is important that straw mulch does not contain weed seeds and to make certain that it does not contain herbicide residues which can take years to fully break down.
3. Results of a study in Virginia (Caldwell and Clark, 1998) suggest that metallic-colored plastic mulches repel cucumber beetles, reducing beetle feeding damage and the transmission of bacterial wilt.
4. Cucumber plants grown in richly-mulched soils harbor fewer cucumber beetles than do those in soils with less organic content (Yardim et al., 2006), perhaps because organic matter fosters diverse populations of beneficial soil microorganisms that trigger the plants internal defenses (Zehnder et al., 1997).
5. A field-plot trial found that intercropping cucumbers with corn and broccoli reduced striped cucumber beetles substantially, compared to plots planted in a monoculture of cucumber
6. Insecticidal soaps sprayed at 5-day intervals, beginning when seedlings emerge or after transplanting and continuing spray schedule until vines run. If rain occurs within the 5-day period, repeat the treatment promptly and then return to the regular 5-day treatment interval. A Homemade version of this spray is 1 Tbls. Murphy’s Oil Soap to 1 Quart Water.
To read more about success with cucumbers, go to https://www.morningagclips.com/grow-delicious-cucumbers/
Just a reminder, our office is now in a new location. Our address is 1325 E. Kemper Rd. Suite 115, Cincinnati, Oh. 45246. Our phone number remains the same 513-772-7645.