ALMOND PMA 2001
PROGRESS REPORT
The Management Team of the Almond Pest Management Alliance
started this project year with a meeting in Modesto on March 7, 2001.
At that time team members reviewed progress from October 2000 and made
plans for the upcoming growing season. Dates
were set for the upcoming spring field days at the three regional trials, with
some discussion about possible meeting topics.
The timing and content of the spring newsletter was the next topic with
emphasis on the importance of the newsletter in educating growers about reduced
risk practices. Preliminary results
of the 1999 grower telephone survey were presented to the group and September 6,
2001 was agreed upon for the next team meeting.
The September 6 meeting was held at UC Davis where progress
from April to September was presented by individual members.
Possible dates for fall dormant spray field days were discussed, with the
possibility of holding two meetings in the Sacramento Valley to reach all area
growers. Funding for year five of
the project was the next agenda item with unanimous agreement that a fifth year
was necessary for success of the project. It
was decided that the findings of the project would be incorporated in an article
co-authored by the farm advisors and then published, possibly in scholarly
journals as well as agricultural and mainstream press with the topic being
“Lessons Learned from the Almond PMA”.
Updated information from the grower telephone survey was again discussed,
including the division of respondents into specific growing regions and specific
farm sizes, and the presentation of data tables with
and without ‘ambiguous cases’ included.
A specific date for the next Management Team meeting was not set.
The following is a summary of newsletters, articles, and publications from January 2001 to the present. An article in Ag Alert, January 2001, the California Farm Bureau’s newsletter, and an article in February’s California Farmer, highlighted the two dormant season field meetings that were held in the Sacramento Valley. The successes of the Almond PMA in helping to educate about the need to reduce winter pesticide runoff was mentioned as well as detailed instructions on how to save money on fertilizer costs. Also in February, the Modesto Bee, printed an article about the Almond PMA receiving another year of funding from California DPR to help in reducing pesticide use without impacting farmers economically. In Rohm and Haas’s spring newsletter “PCA Pipeline”, information about the upcoming approval of their product, Confirm, for use on almonds, was associated with the move away from Organophosphates touted by the Almond PMA. In addition, the Almond Board of California’s spring newsletter included a page detailing the structure and funding of the PMA and noted some successes of the program’s innovative approaches to reducing toxic pesticides used in almonds.
This demonstration site continued, for a fourth year, to
serve as a central focal point for the Almond Pest Management Alliance project
in the Sacramento Valley. The
orchard will continue to demonstrate reduced risk practices and pest levels were
again compared across five treatments.
These treatments consisted of a grower standard, a reduced risk, an
organophosphate applied in the dormant season, an organophosphate applied during
the dormant season and again at hullsplit, and a no spray treatment which was
added for this growing season.
The demonstration site is 49.5 acres with a division
splitting the block into a 27 acre western block and a 22.5 acre eastern block.
The 27 acre block was managed using the current techniques practiced by
the grower with ½ acre set aside as an untreated check.
In the 2000-2001 season it turned out that the grower did not use any
sprays in the grower standard, so the management of the ½ acre check was the
same as the whole 27 acre block. Of
the 22.5 acres, 12.5 acres was managed using a reduced-risk strategy which
included a Bt spray at bloom. Of
the remaining 10 acres, five acres received a dormant organophosphate
application, and five acres received a dormant organophosphate as well as an
organophosphate hullsplit application.
Monitoring and sampling for evidence of insect pests
continued as before. Of the
numerous sampling methods used, none showed any more pest problems or damage in
the reduced risk or no spray treatments as compared to the OP treatments.
Some of the methods used to reach this conclusion were: 1) Dormant spur
sampling: Spurs were collected from
each treatment block and inspected for mites, San Jose Scale, Peach Twig Borer,
and European Fruit Lecanium. 2)
Mummy counts: Average number
of nut mummies remaining in trees tabulated for each treatment.
Mummies are an overwintering site for NOW.
3) Trap counts during the growing season: Traps for SJS, PTB, and NOW placed in each block and trap
catches counted weekly. 4)
Harvest sampling: 500 nuts collected from each treatment at harvest, inspected
for damage, and the damaging insect identified.
In addition, a satellite project was created in an area with pressure
from European Fruit Lecanium. The
project consisted of three treatments, an untreated check, and oil spray at two
different timings. Monitoring
showed that parasites were controlling the EFL and no additional sprays were
needed in any of the treatments.
The Stanislaus County PMA trial continued into the third
season with treatments similar to the first two years.
The pest management programs are replicated three times within a 120 acre
Nonpareil:Carmel orchard west of Modesto. Each
plot is about 13.5 acres in size. The
treatments are:
1) Grower’s Standard Practice: This pest management program is fairly common in the Northern San Joaquin Valley. This grower applies a May spray directed at PTB instead of the more common hull split spray for NOW.
Pesticide treatments include:
¨ A dormant application of Asana (a pyrethroid), 6 gallons of oil, & 8 lb. Kocide.
¨
A May spray with an organophosphate (Lorsban).
¨ Omite if needed for mites.
¨
Lorsban for ants.
2) Soft Program #1: In these areas, we use “reduced risk” pesticides. Specifically, pesticide treatments will include:
¨ A dormant application of copper & oil.
¨ A “bloom” spray of Success at ~ 30% PTB emergence (piggy-backed with fungicides).
¨ A May spray of Success.
¨ Agri-Mek if needed for mites.
¨
Clinch (Abamectin) bait for ants.
3) Soft program #2: Pesticide treatments will include:
¨ A dormant application with oil only.
¨ Two “bloom” applications of Bt (20-40% PTB emergence & ~ 80% emergence) piggy-backed with fungicide sprays.
¨ Two May sprays of Bt (300-350 & 450-500 DD after biofix).
¨ Oil for mites if needed.
¨
Esteem bait for ants if needed.
4) Untreated
¨ No dormant copper, oil, or insecticide application.
¨ No bloom Bt applications.
¨ No May or hull split sprays.
¨ Oil for mites if needed.
¨
Esteem for ants if needed.
Mummies were removed and destroyed in all treatments.
Cover crop management, fertilization, and fungicide treatments are the
same for all treatments other than no dormant copper was applied in “soft
program #2” and the “untreated” treatments.
Monitoring:
Each plot has two PTB pheromone traps, two San Jose Scale pheromone traps, four sticky tape traps for S.J. scale crawlers, and two NOW egg traps for a total of 90 traps in the trial. These traps are monitored throughout the season (March through October). In addition, mites and mite predators are monitored bi-weekly with the presence / absence leaf sampling technique. Ants are monitored periodically using hotdog bait traps.
Summary of 2000 Insect Populations
Peach twig borer (from the over-wintering generation) are roughly twice as high in the areas where no dormant insecticide was applied. Although this has occurred in the past two years, PTB numbers are about the same in all
treatments by harvest. In the first two years, we have seen approximately twice as many Encarsia scale parasitoids in the “soft” programs verses the program with the dormant pyrethroid treatment. So far this year Encarsia numbers are fairly equal in all treatments. Male San Jose scale adult numbers are very low in all treatments. In Stanislaus County, it is rare to find an orchard with a San Jose scale problem due to the high parasitoid populations in the area. Time will tell if the higher scale parasite numbers in the “soft” treatments will keep the San Jose scale under control as well or better than the grower’s standard practice.
Agrimek was applied on June 12 to all three reps of Soft
treatment #1. Agrimek must be
applied while leaves are still soft to maximize absorption and residual
effectiveness. Unfortunately this
means the material is often applied unnecessarily.
Omite was applied to hot spots in the standard practice treatment in
early August. Although mite
populations were not at treatable levels, Omite has a thirty-day pre-harvest
interval and had to be applied as an insurance spray.
Spider mite hot spots were treated with potassium nitrate and oil as they
became evident in soft treatment #2.
At harvest, 1000 almonds were randomly collected from each replication (3000 per treatment) and examined for insect damage. Reject levels for all treatments were very low. There were no differences between treatments in percent damage due to NOW, PTB, or ants.
Conclusions:
After 2 ½ years of intensive monitoring, we have not seen
an increase in any pest in the “soft” treatments compared to the standard
grower’s practices. There also
have not been any differences in rejects due to PTB or NOW at harvest. It is clear San Jose scale parasitoids are significantly
reduced in areas where a pyrethroid is applied in the dormant period and an
organophosphate is applied in-season. In
Stanislaus County, almond and stonefruit orchards rarely have significant damage
from San Jose scale whether orchards are treated with insecticides or not.
However, in areas where San Jose scale is a serious threat, growers
should understand that the use of some insecticides could exacerbate their scale
problems.
The cost of the Bt program is almost identical to the grower’s standard pesticide program if it can be included in normally scheduled fungicide sprays. If pyrethroid or organophosphate sprays cause an increase in mites and thus necessitate a mite spray, a Bt program could prove to be more cost effective. The intermediate treatment is twice as expensive as the other two programs. The costs of Success and Agrimek exceed their alternatives. In addition, Agrimek must be applied early in the season as a preventative treatment, often leading to unnecessary applications.
The
purpose of the PMA project in Kern County is to demonstrate a reduced pesticide
input versus a conventional pesticide program in a young almond orchard.
We
have been collecting and processing data for navel orange worm (NOW), peach twig
borer (PTB), San Jose Scale (SJS), webspinning spider mites and other pests from
a reduced pesticide and conventional pesticide program.
We have also evaluated the value of cover crops in both reduced pesticide
and conventional programs. These
two treatments have been established in a 160 acre orchard which is divided into
80 acres of hard shells and 80 acres of soft shells.
There are two replications of 20 acres each for the reduced pesticide and
conventional pesticide treatments.
The
reason we want to continue collecting and processing data for year five is
because we want to demonstrate that large scale reduced pesticide programs can
control target pests, can be practical within production systems, and can be
economically competitive.
The
data from the past three seasons has demonstrated that reduced risk pesticides
such as oil, BT and sanitation can control San Jose Scale, PTD and NOW.
Our data also shows that webspinning spider mites can be controlled
successfully with western predatory mite releases.
Based on four year’s data, one can conclude that almonds in Kern County
can be grown without the use of organo-phosphates and miticides.
We
need year five to collect data from a non-dormant spray treatment which was
established two seasons ago. We
want to determine how far we allow the San Jose Scale population to go without
damaging fruiting wood. We also
need five years of data to demonstrate to our grower that spider mites can be
controlled using the western predatory mite releases.
The
fifth year will validate monitoring, an important tool to control key pests
using low risk pesticides. Also
during the fifth year, we will start collecting teaching materials for the
development of a monitoring guide.
Orchard
monitoring is the key to reduce or eliminate organo-phosphate sprays.
It is also the key for the adoption of reduced pesticide risk program.
One of the problems of monitoring is its cost and intensity. The intensity of monitoring requires four hours per acre
which is equivalent to $40.00 per acre. This
may not be acceptable by most growers. What
may be acceptable is to train his low wage employees to monitor his orchard.
We can develop a monitoring guide, both in English and Spanish, and
organize training workshops.
SUMMARY
In summary, the Almond PMA has many accomplishments to be proud of in the 2000-2001 season. The project has shown that reduced-risk programs using lower inputs of OP pesticides have had no more pest problems than the conventional methods of growing almonds, which sometimes use two or more sprays of pesticides to control insects. There is increasing interest in these programs as shown by the well-attended field days and articles published in mainstream and agricultural publications. The PMA, with another year or two of research and demonstration, will create a database of information about reduced-risk scenarios that will be very valuable to almond growers throughout the state.