WALNUT NEWSLETTER, January, 2002
New IPM Implementation Projects Initiated in California Walnut Orchards
Steve Wulfert and Pat Weddle
moth has been a serious pest of walnuts in California for as long as the crop has been grown in the state. While some varieties are more susceptible
than others, all varieties can be damaged when conditions are favorable
for codling moth development.
growers have relied on chemical sprays to control this pest. Over the
years, chemicals such as nicotine sulfate, lead arsenate, DDT, organophosphates
and carbamates have been used to control codling moth in walnuts. As each
of these materials was used, codling moth either became more tolerant
of its use and efficacy was lost or the chemical was removed from the
market because of environmental or worker safety concerns.
moth resistance to many of the organophosphate insecticides used in walnuts
has been demonstrated. This resistance has been shown to cross over to
some insecticides not yet registered for codling moth such as certain
insect growth regulators (IGRs).
regulatory pressure against the use of organophosphates important to walnut
pest management continues. Recently, US-EPA proposed a four-year phaseout
of azinphosmethyl (Guthion®) in walnuts. Further regulatory actions
are likely. Consequently, walnut growers will be availing themselves of
new pesticidal technologies including mating disruption for codling moth.
Integrated Pest Management (IPM) strategies have included the research
and testing of several nonchemical interventions to control codling moth,
including mating disruption techniques. Mating disruption relies upon
the same codling moth pheromone that growers have used for the past three
decades to detect and monitor codling moth activity in their orchards.
Using a small dose of the pheromone in a sticky trap enables growers to
attract and capture male codling moths in their orchards. This knowledge
of codling moth flight activity provides a decision- making tool for the
necessity and timing of chemical sprays. Rather than applying long-residual
cover sprays, the grower can target peak flight activity.
In California, control of codling moth with pheromone mating disruption
began in the early 1990s on apples and pears. Growers were experiencing
increasing difficulties managing codling moth in their orchards due to
emerging resistance to organophosphates. By the late 1900s mating disruption
was being successfully used on approximately 20% of California pear acreage.
In 2000, 95% of the pear acreage in the state's largest pear-growing region,
the Sacramento‚ San Joaquin Delta, managed codling moth by using pheromones
supplemented with conventional insecticides.
there are several formulations of mating disruption products that are
or soon will be commercially available for walnut growers. Isomate C+®, from
Pacific Biocontrol Ltd. is a twist tie hand applied formulation that
is widely used in tree fruit. This formulation must be placed in the tops
of trees for optimum effectiveness. 3M Canada is developing and Suterra
Ltd. (formerly Consep) is currently providing sprayable formulations of
mating disruption materials that can be applied with conventional spray
equipment. 3M expects to have registration of its sprayable mating disruption
product in 2002. In addition, Suterra also has a formulation
Lure Catches Both Male and Female Codling Moths During the past two years,
Trece, Inc., a Salinas, Calif. company specializing in insect monitoring
products, in conjunction with Drs. Doug Light and Allen Knight of the
USDA-ARS, have developed a codling moth attractant that is based on a
kairomone or host plant attractant rather than a pheromone or sexual
attractant. This new lure, the DA lure, will provide walnut growers
with an effective tool to monitor codling moth in traps where pheromone-mediated
mating disruption would otherwise compete with the typically used pheromone-baited
codling moth trap. In addition, the DA lure captures both male and female
codling moths, allowing the pest manager to further refine spray timing.
Walnut Pest Management Alliance Project (PMA)
The Walnut Pest Management Alliance (PMA), a research and field demonstration
project jointly supported by the Walnut Marketing Board, UC Cooperative
Extension, UC-Berkeley, USDA-ARS and the California Department of Pesticide
Regulation, has shown much promise for the use of mating disruption as
an economically viable tool in the management of codling moth. Additionally,
the PMA has demonstrated the viability of the DA lure as an effective
monitoring tool in disrupted orchards. As the Walnut PMA enters its fifth
year, many involved have expressed interest in providing its benefits
to more walnut growers by expanding commercial implementation of PMA findings.
for a wealth of information on walnut pests and pest management
for information on ordering a wide variety of pest-monitoring traps
and other tools
for the Center for Agricultural Partnerships, a nonprofit organization
whose mission is to help working farmers improve productivity and
Walnut IPM Expansion Project (WIPMEP)
A project to expand implementation of new pest management technologies
in California walnuts has recently been initiated by the Center for Agricultural
Partnerships (CAP). Dubbed the California Walnut IPM Expansion Project,
CAP, in close cooperation with pest control consultants and their grower-clients,
will be conducting ground-up orchard- based implementation of new pest
management technologies emphasizing the use of mating disruption for codling
moth and adoption of new monitoring strategies such as the DA lure. Specifically,
the project will support walnut PCAs and their growers to optimize their
commercial use of these new technologies in their individual orchards.
walnut implementation project will work with key growers and their pest
control consultants throughout California to understand their specific
pest management needs and customize PMA findings to meet these needs.
This will be done by applying a proven process of:
what growers require to implement new technologies;
understanding how pest management decisions are made;
gathering the information necessary to support the desired change;
measuring progress in real time;
providing a constant flow of information between and among growers;
what works and what doesn't while adapting to the constantly changing
initial project will encompass about 1,000 commercial walnut acres throughout
the state. Once the implementation process is tested and refined on this
initial acreage, the project will expand to at least 25,000 acres in subsequent
in cooperation with Weddle, Hansen and Associates, Inc., a California-based
agricultural consulting firm specializing in orchard implementation of
IPM, will manage WIPMEP. Currently, three well-known walnut experts have
agreed to serve as the WIPMEP's regional coordinators: Steve Wulfert of
Diamond of California in the Sacramento Valley; Joe Grant of UC Cooperative
Extension in the northern San Joaquin Valley; and Steve Sibbett, UC Cooperative
Extension Emeritus in the southern San Joaquin Valley. These regional
coordinators will identify key grower and PCA cooperators who will be
the core of the implementation effort. In addition, the coordinators
expertise is providing important insight and guidance for CAP's management of WIPMEP.
WIPMEP findings and knowledge will be shared with cooperators through
frequent personal communication and e-mail among project participants.
Small regional grower/ PCA meetings will be important to broader project
communication and expansion. Finally, the walnut industry will learn of
the project's activities through industry newsletters and field days.
The Center for Agricultural Partnerships (www.agcenter.org) is a 501(c)(3)
nonprofit organization whose mission is to help working farmers improve
the productivity and profitability of their farms through the use of environmentally
and economically sound growing practices that reduce pesticide risks,
improve water quality, create healthier ecosystems and improve the well-being
of the farm community.
Wulfert is Diamond's field representative for the Northern Sacramento
Valley. Weddle is founder and president of Weddle, Hansen and Associates,
Inc., an agricultural consulting firm established in 1975 to develop and
implement strategies, tactics and policies that emphasize biologically
intensive IPM. In 1999, the firm received the California Department of
Pesticide Regulation's IPM Innovator award. Weddle holds bachelor's and
master's degrees in entomology from UC-Berkeley.
For more information please contact
Patrick Weddle at email@example.com