Biological control with
beneficial insects makes dollars and sense. No orchard, even one that is
chemically sprayed, can afford to be without biological control. Growers
transitioning from toxic pesticides towards greater reliance upon biological
control by natural enemies typically report fattening up bottom lines during
the first two years with 50-75% pest control cost savings.
Difficulty achieving
satisfactory pesticide spray coverage is incentive enough to experiment with
biological control agents that seek out pests with the precision of
laser-guided missiles. Costs of sprays, the hassle of scheduling sprays when
workers are not present, managing residue and
resistance problems, particularly the resistant codling moth, can
be avoided with greater reliance upon
biological pest control solutions.
Improved plant vigor and
health may also be noted when pesticide stresses on plant physiology are
removed. Public and worker liability risks, even insurance costs, may be
reduced. Besides safety and profit benefits, adding biological control with
natural enemies as a pest control input can also provide valuable public relations and marketing benefits as a
"green", environmentally-friendly
alternative to conventional chemical control.
BIOLOGICAL CONTROL IN
ORCHARD AGRO-ECOSYSTEMS
Releasing Rincon-Vitova's
beneficial insects into walnut agro-ecosystems is part of a sound profitable
strategy for achieving biological control and minimizing crop damage.
Rincon-Vitova's natural enemies help police pest populations and stabilize
orchard ecosystems, bringing predator and prey
(pest) into better ecological balance.
Walnut trees provide a favorable environment for a wide variety of
organisms, including several hundred insect and mite species, most of which are
beneficial -- e.g. pollinators increase fruit set, antagonists suppress pests
via niche competition, scavengers turn debris into vital soil humus and are
part of the food chain, an alternative food source for beneficials when pests
are absent. In orchards where pesticides have not killed off the predators and
parasites, most potential pests go unnoticed, as they are so effectively
squelched by resident beneficials.
Of the several hundred
arthropod species residing in walnut orchards, only three (e.g. codling moth)
are key pests directly attacking the fruit. These key pests are attacked by a
wide array of general feeding predators and
parasites. Rincon-Vitova's insectary-grown beneficial insects (all
natural, none genetically engineered) supplement indigenous orchard biological
control organisms and shift the ecological balance towards sustainable
biological pest control by natural enemies.
FARMING WITH BENEFICIALS
Maximizing the diversity and
distribution of selected plant species -- e.g. planting covercrops or
tolerating certain weed species between trees at critical times instead of
herbiciding or discing the orchard floor completely clean -- is a farming
technique useful for increasing orchard biological control. The strategy behind
cover cropping vis-a-vis pest control is increasing resident insect and
arachnid micro-wildlife, thereby expanding the food chain and supporting a
larger army of beneficial pest-fighting arthropods. Thus, after cleaning up
walnut aphids in the trees, brigades of predators and parasites can find
shelter and sustenance on cover crops, and be available to fight future
infestations in the trees.
The best cover cropping
strategy may vary from area to area, and is best selected in consulation with
pest control advisers and other sources knowledgeable about integrated pest
management (IPM) techniques like habitat diversity and refuge management.
Rincon-Vitova's philosophy is that orchard cover crops and cultural practices
must be designed to grow beneficial organisms in ecological environments that
closely emulate the natural systems in which they evolved.
At Rincon-Vitova, we
enthusiastically recommend consideration of legume green manure cover crops.
Besides injecting nitrogen into the soil and promoting formation of nourishing soil
humus, legumes and mixtures of legumes, grasses and weeds can be managed to
reduce orchard pest problems. For
example, by periodically alternately cutting every other border of leguminous
cover crops, weeds can be kept from going to seed, while at the same time
encouraging composting organisms. Composting organisms become part of the food
chain, nourishing biological control organisms ranging from beneficial
arthropods to predatory nematodes and fungi that aid in the biocontrol of soil
and foliar insects and diseases, such as the walnut blight caused by Xanthomonas campestris.
Rincon-Vitova's
insectary-grown beneficial insects (all natural, none genetically engineered)
are intended to be part of a larger orchard integrated pest management (IPM)
strategy, augmenting naturally occurring populations of predators and
parasites. Our beneficial insects are not intended to be used as pesticides,
and we oppose government regulatory agency expenditures of taxpayer monies
(e.g. Cal-EPA) to regulate these tiny pest-eating farm animals as toxic
chemical pesticides subject to the same costly regulatory policing policies as
the toxic chemicals that brought on the current environmental crisis and
consumer distrust of agriculture -- beneficial insects are part of the
solution, not the problem.
Rincon-Vitova's beneficial insects are not designed to be magic bullets
applied like pesticides for instant pest control. Successful sustainable biological control is an ecological process,
and inoculative releases of Rincon-Vitova's
beneficials into the orchard ecosystem to augment existing natural controls is but one component of a
larger sustainable ecological farming
system that may take three to five years to establish. Farming ecologically with Rincon's biological control
inputs gets easier the second and third
year, as a reservoir of natural biological control organisms becomes established.
After the initial first year
biocontrol inoculation, which is best planned
out with an IPM specialist who can monitor progress and advise on
release dates etc., smaller annual
maintenance releases of predators and parasites may subsequently suffice to get a headstart on pests and
compensate for biocontrol losses to
weather, orchard sprays, pesticide drift etc. Besides helping integrate
sustainable biological control into your farming system, an IPM practitioner can provide guidance on
least toxic, low residual sprays and
reduced dosages of conventional pesticides that minimize disruption of biological control. Continued attention
is advised to nurture biological control organisms from year to year and detect
new pest invasions.
Careful monitoring and
sampling of the progress of biological controls is important because not all
walnut trees or parts of groves get pests at the same time. It is often
possible to identify pest "hot spots" that can be targeted for
treatment with larger numbers of beneficials or spot-treated with least toxic,
low residual spray materials. Knowledge inputs -- e.g. publications like the
IPM Practitioner (BIRC, P.O. Box 7414, Berkeley, CA 94707) and the University of California's Integrated Pest
Management for Walnuts manual -- and staying on Rincon-Vitova's customer list
are also recommended to keep you up to
date on the latest advances in managing pest
natural enemies. To be most
effective and sustainable, biological pest control is best designed into an
area. Alfalfa is the beneficial insect nurse crop for many agroecosystems.
Spraying "insectary" crops like alfalfa is a guaranteed recipe for
major pest infestations in all area crops; the media seems to have missed this message in the recent
sweetpotato/poinsettia whitefly
scourge.
Slight modifications in the
way one farms can emulate more natural systems, and encourage beneficial insect
armies to attack walnut pests. For example,
planting cover crop or alfalfa refugia (safe havens that are never
sprayed) mimics the natural movement of
beneficials from crop to crop. Biological
control is maximized when alternate crops act as field insectaries,
growing large populations of
pest-fighting predators and parasites. Refuges of alfalfa and other legumes attract large numbers of aphids, mites,
and worms (none of which attack
walnuts) that nourish general predators which can move into the trees to eat walnut pests.
A form of intercropping
known as strip cropping (e.g. strips of cover crops between at least some tree
rows) and maintaining small fields of unsprayed alfalfa are ecological farming practices Rincon-Vitova recommends
to create on-farm insectaries, growing
your own free supply of hungry predators and
parasites to devour pests. General predators that feed on a wide variety
of prey eat early season pests in
unsprayed alfalfa and cover crops. Several
generations later their offspring form the basis of biological
controls that enter the canopy of new
spring growth occurring in walnut trees.
Alternate strip harvesting
of alfalfa and cover crop beneficial insect
refuges (safe havens that are never sprayed) keeps the plants attractive
to arthropod food sources that nourish
beneficials throughout the season. As
the season advances, begin mowing alternate strips when cover crops or alfalfa begin to bloom; cut half and let
this start to grow back before mowing
the alternate strips. Avoid broad spectrum pesticides at all costs in early season for maximum production of
predators and parasites. This
"battle of the bugs" in adjacent crops takes place without
damage to the walnuts.
USING RINCON-VITOVA'S
BIOLOGICAL CONTROL INPUTS
Maintaining biological
control in walnuts is an ongoing process involving introduction and conservation of natural enemies and careful
monitoring. Periodic maintenance release
of insectary-grown beneficials timed to focus
on developing pest hotspots aids in season-long biocontrol. Conservation
of natural enemies is facilitated by
phasing out hard pesticides interfering
with biological control. Repeated spraying of hard-to-kill resistant
pests devastates beneficials, and in
the longrun creates even more pests.
Where walnut's beneficials
are destroyed by spray programs or starved away by lack of alternate prey,
releases of Rincon-Vitova's green lacewings and other beneficials helps restore the natural checks and balances found
in unsprayed ecosystems. Early season release of insectary-grown beneficials is
the backbone of reestablishing biological control. It is like restocking the
fish pond when one starts releasing Rincon's beneficials to rescue such
natural-enemy-depleted farms from the pesticide treadmill.
Rincon-Vitova Insectaries
tries to make the transition from pesticides to ecologically-based biological control as smooth as possible by
continually collecting new strains of
beneficials from heavily sprayed agroecosystems. Though we do not specifically test natural enemies for ability to
withstand chemical sprays, we believe
that some of our insects, particularly our
green lacewings, great all-around predators, have been successful
in transition situations due in part to
this hardiness and ability to withstand
some chemical residues.
General predators such as
green lacewings and lady beetles are released to insure timely presence when aphid prey are in the cover crop.
Ideally, releases are started early when
the first pests enter the field. These
early releases are forced into the trees when walnut aphids appear.
The same beneficials control spider
mites after aphids come under biological
control. Later season worm control is an additional benefit of
letting small early season populations
of beneficials expand their numbers in a
pesticide-free environment.
If it is necessary to knock
runaway pest populations down to levels that
small populations of newly-introduced beneficials can easily mop up,
use least-toxic, low-residual spray
materials. The goal of spraying (selective
use of least toxic pesticides) is lowering pest populations to
tolerable levels, not pest eradication.
Low pest populations and innocuous alternate
prey are necessary to feed biological control organisms. Without
prey, predators are scarce. Hence, it
is essential that a few minor pest
situations develop, in order to obtain and maintain a buffering natural enemy complex within the walnut ecosystem,
and control major pest problems as they
develop.
A natural enemy complex of
several dozen species building up over time may be necessary for sustained
biological control of key caterpillar pests, such as the codling moth. An
advantage of releasing Trichogramma reared in Rincon-Vitova's insectary is that
this pinhead-sized parasite kills codling moth in the egg stage before it can
damage fruit or nuts. Trichogramma is
one of Rincon's specialities. Releases work best in conjunction with natural
enemy conservation measures such as avoiding harsh sprays toxic to indigenous
beneficials and growing cover crops with nectar to nourish wasps attacking
codling moth larvae and pupae.
Rincon started out rearing
Trichogramma for cotton growers in 1960, and has since reared several
Trichogramma species adapted to a wide variety of crops and pests. One of our
most popular strategies is initially releasing large numbers of Trichogramma
and green lacewings to colonize groves, then following up with a series of
smaller releases to ensure long-term establishment. We currently recommend purchase of Trichogramma platneri for
release in west coast orchards against codling moth and a wide variety of fruit
and leaf worms, including navel orangeworm, redhumped caterpillar, fall
webworm, Oriental fruit moth and twig borers. Trichogramma minutum is the
species of choice for the east coast.
Customers on accounts are
informed through periodic mailings of new beneficial species, some of which are
so scarce that only very small quantities can initially be provided for
inoculation. In addition, where demand is sufficient, we can on special request
collect or obtain rarer natural enemies not normally available commercially.
Technical bulletins are
available for all the beneficials that we sell. A quality control specialist works to insure that the best
possible product is sent out. Nevertheless, sometimes shipments of fragile
insects can arrive injured or otherwise not meet expectations. As we stand
behind all product shipped, please feel free to contact us should you ever feel
that there is a problem or that a replacement may be necessary.