Cucumber Beetles

This is the time of year that adult cucumber beetles will begin to appear in the garden. You will first notice the leaves of cucumber and squash or melon plants being eaten.  The mated beetles will lay eggs at the base of the plant.  About this time of the year, the eggs will hatch and the larvae will dig down into the soil and start feeding on the roots of the plants for about six weeks.  After they emerge as adults, the next problem they cause is spreading disease.


Spraying with chemicals or organic sprays is only a bandaid to the real problem.  If your soil has a healthy community of predatory nematodes, they will control the beetles.  Predatory nematodes feed on the larvae of beetles.   Last year I had cucumber beetles and squash beetles on my plants.  It was not an infestation but there was damage.  This year I have not seen any damage yet.  I did find 3 Colorado potato beetles on my potatoes.  Last year my potatoes were badly damaged but survived.  By adding our vermicompost to the soil, I am reintroducing the life that is necessary for a healthy soil community.


Cucumbers

Zucchini

Water, erosion and earthworms

It has been raining here consistently over the past week and the forecast for the upcoming week is predicting more rain.  Here are some interesting facts about water retention in soil, erosion and the role that earthworms play in the soil's ability to hold water.

Earthworms improve water absorption and prevent erosion.  The castings increase the water stability of the soil, because earthworms castings can take a direct hit by a raindrop and maintain their shape, which reduces erosion and runoff and helps the soil absorb water.  A research study conducted in Minnesota showed that earthworms added to cornfields increased water absoption rates 35 times over control fields without the earthworms within a six-week period.  In soil in a field with 100 night crawlers per square yard, 2 inches of water (a very heavy rainfall) could be absorbed by the soil in 12 minutes.  The same soil without earthworms took over twelve hours to absorb that much water (USDA National Soil Tilth Lab).  Another study found that if the top 3 feet of soil contained 25 percent macropores (earthworm burrows), then that soil should  be able to absorb at least a 9 inch rainfall without runoff.  Note that tilling the soil not only kills beneficial fungi but reduces the number of earthworms, which affects runoff.  One study showed that on a sloping field with no-till practices, there were 155 earthworm holes per square yard and an average runoff of 0.08 inches per year.  This compares to a tilled field with 6 holes per square yard and 4.9 inches of runoff per year (the average rainfall for this area is 39.4 inches).

To attract and promote earthworms, the soil needs to be mulched with organic mulches that help stabilize soil temperature and moisture.  The mulch provides food and shelter for earthworms.  Native mulch and compost are the most valuable for promoting earthworms.  The increased particle surface area of the small particle sizes in native mulches that have been ground also allows for the greater microbial activity that is preferred by worms.  Worms ingest mulches for the microbes that inhabit the surfaces.

Some scientists now believe that earthworms have the potential to eliminate soil erosion.  This could save society billions of dollars in erosion control, reduce pollution from dangerous synthetic chemicals, and improve the environment.

The secret to attracting earthworms to your soil in to restore the diversity of soil life that is needed for a balanced soil foodweb.  We are building that diversity into our worm bins continually.  Our goal is to provide the building blocks for a healthy soil community.