Horticulture Hotline 07/27/15
Bill Lamson-Scribner
Biopesticides (also called bioscience products) are
pesticides that are found in nature. Do you remember studying how the black
walnut tree exudes its own preemergent herbicide (juglone that causes an
allelopathic effect) to keep other plant life from growing underneath it and
competing with it? This is definitely
the way of the future!
The most common biopesticides that you might have heard of
in the past would be pheromone traps for catching flies or Japanese
beetles. Pheromones are a natural chemical
attractants (usually sexual) that animals as well as insects produce. You put
these attractants on a glue board to attract flies and Japanese beetles and
they get stuck. Bt or Bacillus thuringiensis is a bacteria that controls many
different worms, caterpillars, mosquito larvae or Lepidoptera insects. Diatomaceous earth is a natural contact
insecticide derived from microscopic plankton or algae with silica skeletons. Roaches, ants, fleas, and snails walk across
this product and it causes abrasions to their exoskeleton and they dry out and
die.
Many of the major chemical manufacturers are spending more
money developing these types of products (finally) because they are easier to
get approved through the EPA, saving them money in the long run.
Most bioscience products are very specific to certain
pests. In some cases it is required that
you use them more frequently because the product breaks down in the environment
very quickly. Diatomaceous earth on the
other hand lasts a very long time. It is important that you know the life cycle
of the insect or pest that you are after because some bioscience products only
attack the pests at a certain stage in their life cycle.
Some bioscience products that we had had a lot of success
with include; Harpin protein, Neem Oil, Spinosad, beneficial nematodes, various
oils and insecticidal soaps. Other
bioscience products called bionutritional products or biostimulants that we
have seen great success with include; humic acid (Possum Hume), seaweed
products (liquefied seaweed and sea kelp products), and amino acid
products. SeaHume (a combination or
seaweed and humic acid) is a proven performer in the Lowcountry.
To give you an example of a bioscience product, Harpin protein
(found in Mighty Plant) is a bacteria’s (fire blight) waste product (poop) that
is sprayed on the plant. The plant
thinks it is being attacked by a bacteria so it goes into its defensive
mode. The plant’s cuticle thickens
preventing attack from certain insects, fungi and bacteria. This cuticle thickening also conserves
water. The plant also flowers profusely
in an effort to create seeds to perpetuate its species (war time babies) and
also grows a larger root system. Since
most people grow plants for flowers, this is an obvious benefit. A plant that has been treated with Harpin protein
is more drought tolerant, has better flowers, has better foliage, can resist
certain fungus and insect attacks, and has a stronger root system than an
untreated plant.
Always read, understand and follow product label. The
product label is a Federal Law.
