Flea Beetles & Pill Bugs

Flea beetles on cabbage

The rains continue. Despite the wet and cool weather, a number of gardeners have mentioned to me the appearance of the usual population of flea beetles in their gardens.

Flea beetles comprise a large group of leaf beetles of the family Chrysomelidae.  Probably the most common flea beetles that backyard gardeners encounter belong to the Phyllotreta genus and show up on brassicas (cabbage, broccoli etc.)  and solanaceous plants (tomato, potato, eggplant etc.).

These varities of flea beetles are about the size of pin heads, typically black and have strong hind legs that they use to jump, like fleas, if disturbed.  First signs of their presence frequently will be damage to the surface of plant tissue or small pin holes through  leaves.  Adult flea beetles leave their eggs at the base of their preferred plants. When the eggs first hatch, the young initially feed on the roots and root hairs of plants; and then, as adults, they migrate up to the  foliage. There can be multiple generations during a growing season.  Larvae  over winter in plant debris left in gardens at the base of the plants they lived.  

A variety of organic technques can be employed to control, but not eliminate,   flea beetle populations. These include:

• adjusting planting times:  sow seed early  before flea beetle eggs hatch  or delay sowing to let eggs hatch before larvae have seedlings  to eat;

• tilling soils lightly in spring to disturb larvae; 

• using trap crops - first plant a crop attractive to flea beetles beside where you plan to plant you favorite crops,  e.g. dill  attracts flea beetles,  and the dill can then be tilled into the soil to disrupt a portion of the flea beetle population;

• interspersing companion plantings to  provide flea beetles with alternatives: e.g. dill, marigold and pac choi;

• mulching with straw or grass clippings can interfere with beetle egg deposit;

• keeping planting beds free of weeds such as wild mustards, a favorite meal for the beetles; 

• adding row covers - these offer some relief,  but soils need to be free of over wintering populations;

• placing sticky traps around plants also offers relief, but will also trap some beneficial insects;

• vacuuming may also reduce their numbers (check this  previous post).

There are also some biological methods to control flea beetles.  There is a common parasitic wasp, Microctonus vittatae, that specifically targets adult beetles. The wasps are a natural control, but not a quick solution.  At the subterranean level, there are also some nematodes that  devour flea beetle larvae as well as  a fungal pathogen, Beauvaria bassiana, that will infect the beetles.  Both of these should be present in healthy soil, but are available from commercial sources.  Finally, some pesticides, like neem,  that are approved for organic use  could be applied.

Pill Bugs

Pill bugs (Armadillicidam vulgare), alias: Rollie-Pollies, are not insects, but actually crustaceans and  members of the woodlice family.  Adults are usually between 1/4" and 1/2" in length, and black to grey in color.  Pill bugs do not lay eggs; females have a pouch that first carries the fertilized eggs and then serves as home to the hatchlings for up to their first two weeks of life. Pill bugs are eaten or preyed upon by birds, toads, spiders and some wasps.

In gardens A. vulgari can be both good and bad.  Pill bugs typically like damp or moist places and eat decaying plant debris - you will typically find them in your compost pile, under rocks and rotting wood. They are generally nocturnal  avoiding warmer daytime temperatures. However, if their population gets too large and there is a lack of decaying plant material in the soil, pill bugs will   eat living plants including many of our favoritge vegetables. Overly wet conditions, like this spring, also seems to engender their taste for  fresh garden salads.

In small gardens and greenhouses the following control strategies can be used:

•  placing plant collars around young plants; 

• removing of plant debris to reduce habitant; 

• reducing humdity levels and/or increasing air circulation (fans & dehumidifiers indoors; staking & pruning outside);

• vacuuming (place a cloth or cardboard sheet around a plant and shake);

• deploying sticky traps, or diatomaceous earth;

• traping  by placing wet, rolled newspapers in the garden at night (pill bugs will congregate   under the newspapers after first eating your eggplants;  and, of course, 

• applying neem or other pesticides. 

And remember:

"On every stem, on every leaf,... and at the root of everything that grew, was a professional specialist

 in the shape of  grub, caterpillar, aphis, or other expert, whose business it was 

to devour that particular part. - Oliver Wendell Holmes

What's in your soil?  Seeds - Heirloom, GMO, Non-GMO, or Hybrid

A recent article in the New York Times' Sunday Magazine  by Dan Barber about genetic modification of seeds suddenly got me worried (again) about

• the seeds I use in my garden, and

• the lettuce that I just bought from the  grocery store because I had run out of  my home grown mix. 

I felt that I needed to refresh/reboot my brain about what the terms "heirloom, hybrid, GMO and Non-GMO indicated. I checked with my principal seed source and was relieved to learn that it, at least, pledge not to use or supply genetically modified seeds (GMOs). The company usually offers also offers between "organic" and "conventionally" grown seeds also accompanied with the pledge taht both are "non-GMO." The difference is that "organic" means the plants supplying the seeds were grown in accordance to some recognized standard, the top standard being that administered by the U. S. Dept. of Agriculture. For plants and seeds, this label means that those plants have not genetically modified, treated with sludge, chemical fertilizers or pesticides, the grower (e.g. farmer has kept detaield records of her/his work, and that the farm has passed a third party's verifying inspection.

FWIW: GMO seed comes from  plants whose DNA has been altered by various processes such as recombinant DNA technology, cell fusion, micro and macro encapsulation - processes that are not realisically possible in nature. A good example is a Monsanto seed corn whose DNA that now contains genetic material from BT (bacillus thuringiensis), a bacteria that is considered to be a natural pesticide.  The corn is actually registered as a pesticide, not as a plant.  Other genetic modifications  are used to make plants reliant on specific brands of fertilizer, resistant to certain herbicides, grow to a given height or ripen within tighter range of days. On the other hand, GMO crops have increased crop yields and produced disease resistant crops in Southeast Asia.  The underlying concerns about GMOs relate to over dependence on just a very limited variety of crops, a few corporate monopolies dominating the seed supply for a large part of the world and the uncertainties of knowing what, if any,  are the long term impacts of genetically modified plants on the natural environment and, of course, humans.

"Conventionally" grown from my supplier means that the seed plants may have had chemical fertilizers or pesticides applied to them but are from  non-GMO sources.  Hybrid  plants can meet organic standards - hybrids are just the result of cross-pollination with closely related plants.  Hybrids usually require multiple generations of breeding for their favored characteristics to become established and become  a reliable variety so that their seed will reproduce a plant like its parent, i.e. be "true to seed."  Most "heirloom" plants are the result of cross-pollinations occuring over hundred or even thousands of years either through natural selection or over just decades with human assistance, but they remain "open pollinated" plants.  "Open pollination" means that if you decide to save seed from your Brandywine tomato for the next season and you also grow either another heirloom, like Amish Paste, or a modern hybrid, like Big Girl, you may not get a Brandywine next year (f1 generation).  In order to keep your "open pollinated" plants true to seed, you need to keep them isolated in some manner from the riff-raft tomatoes growing down the street...

Veggie History:  Strawberries

Source: Cornell U.

It's shortcake season! Volunteer fire companies, church auxiliaries, and garden clubs now are busy posting signs daily along roadsides announcing "Strawberry & Short Cake Festivals," and the red berries  displayed in pint and quarter baskets   fill the stalls at local farmer markets. 

But did you know that these familiar strawberries (Fragaria x ananassa)  are actually an European  cultivar of two crossed wild varieties from the New World?

Native Americans  introduced European settlers to the eastern  variety, Fragaria virginiana. Although the settlers sometimes included it in their gardens, they generally picked the berries in the surrounding woods; and  Europeans returning to the  Old World took plants back to their  gardens.  In the early 18th century, F. virginiana  probably accidentally hybridized with another New World species, Fragaria chiloensis that grew along the West Coast and in South America to produce our familiar F. x ananassa.   This hybrid quickly displaced Fragaria fresca (the "alpine strawberry" common throughout the Northern Hemisphere), in European gardens, it and soon traveled back across the Atlantic.  By the end of 18th century the new strawberry was being sold to gardeners like Jefferson by "plant men" in America. The rest is history, of course; but for a lot more information about strawbe

And remember:

"I eat a lot of fruit because if I fill up on strawberries or an apple, then I'll have one small 

piece of cheesecake rather than two big pieces." - Tom Fridan