Butte County Almond PMA Annual Report Oct. 11, 1999

Butte County Almond PMA

This orchard is approximately 49 acres. The grower standard block is 27 acres, the PMA block is 22 acres divided into a 12 acre soft treatment and a 10 acre organophoshpate dormant treatment. Five of these 10 acres received an organophosphate hullsplit spray. Traps were placed in the center Nonpareil row on the north side of the same tree and monitored weekly.

Treatment Before Monitoring

Conventional Practice 27 acres: On 2/20/99 and 2/26/99 a mixture of Rovral, oil, and 10-52-10 was applied. Rovral was applied at .8 pounds per acre. Oil was applied at 1 gallon and 10-52-10 was applied at 4 pounds per acre. On 3/9/99 Break, at 4 ounces per acre, Condor at 2 pints per acre, and 20-20-20 at 4 pounds per acre was applied.

Dormant Spray: Diazinon was applied at 4 pints, Kocide applied at 8 pounds, and oil applied at 4 gallons per acre on 1/28/99.

PMA 22.5 acres: Rally and 10-52-10 was applied on 2/23/99 and 2/26/99 at rates of 6.4 ounces and 4 pounds per acre respectively.

Soft 12.5 acres: On 3/9/99 Vangard at a rate of 5 ounces, Condor at a rate of 2 pints, and 20-20-20 at a rate of 4 pounds per acre were applied.

Weeds: On 2/5/99 the strips were treated with Round up original at a rate of 2.66 pints per acre. Goal 2xC was also applied at this time at a rate of 6 ounces per acre.

Peach Twig Borer

Dormant 100 spurs samples were taken in December 1998 from each of the four blocks and evaluated for peach twig borer hibernacula. No hibernacula were present in any of the blocks. Peach twig borer traps were placed in the Butte County Pest Management Alliance orchard on March 12, 1999. One trap was placed in each of the four blocks: grower standard, soft chemical, dormant spray, and dormant-hullsplit spray. Traps were monitored weekly, lures changed every two weeks, and liners changed as necessary. The first biofix occurred on April 22, 1999. Subsequent biofix dates are: June 26, August 13, and September 28 (Fig. 1). As of 9/16, seasonal totals of peach twig borer trap captures are presented in Table 1.

Table 1. Seasonal peach twig borer trap captures as of 9/16/99.

Navel orangeworm

Navel orangeworm traps were placed in trees on May 6, 1999. The biofix for this orchard occurred on May 14, 1999. Since eggs were so rapidly detected on the traps, this biofix date may be inaccurate but will suffice for these purposes. On 7/16, 1025 DD, the second biofix occurred and on 8/27 at 1717 DD on new crop nuts, and on 9/15, 2050 DD, on mummies the third biofix occurred (fig. 2). Overall, there were very few eggs detected throughout the orchard. The total eggs trapped for the season in each plot are presented in Table 2. These low populations can be attributed to winter sanitation. Mummy counts taken in February 1999 showed that out of 20 randomly chosen trees in each block, totaling 80 trees, there was less than 1 nut per tree. Winter sanitation is the most effective means of controlling navel orangeworm.

Table 2. Seasonal total of NOW eggs Butte Co. PMA 1999

San Jose Scale and San Jose Scale Parasite

Dormant spur samples showed that less than 10% had detectable scale or parasitized scale in each block. San jose scale traps were placed in the orchard on March 12, 1999. New traps were placed in the tree weekly as the old traps were collected, wrapped in plastic wrap, and brought back to the laboratory to be evaluated under a microscope. The male scale and the parasites were counted using the random blocks provided on each trap. The first biofix for san jose scale was on 4/16/99 and was observed again on 4/22/99. After this date, the male scale did not reappear on the traps until 7/13/99. Parasites were present starting on 6/8/99 in great numbers. The parasite trapping continued for the duration of the season despite the low number of male scale. Season totals show that the grower standard block had the least number of male scale and parasites. The dormant-hullsplit block had a season total of 85 scale but had the most parasites present with 3335 total (Table 3).

Table 3. Seasonal total of san jose scale males and parasites trapped.

Mites

Dormant samples showed that over 50% of the spurs collected in each block had mite eggs present. Mite monitoring began on 6/23/99 and continued weekly until 8/31/99. Monitoring then occurred every other week. At each sampling, five trees per block were chosen randomly and fifteen leaves from each of the five were collected and inspected for red mites, two-spot mites, beneficial mites, and beneficial insects. Differentiation between two-spot mites and red mites were not noted. The total season count shows that the grower standard block had the least mites and the second highest number of beneficial insects observed (Table 4 and Fig. 3). There was an increase of mites and their predators noted on 9/16/99. Another sample was taken and showed there were no mites present. Since the population increase occurred late in the season, and defoliation was minimal, these mites will not be detrimental to tree performance next year.

Table 4. Seasonal total of predator mites/beneficial insects and european/two-spot mites.

Ants

Ant traps were placed in each block in the orchard on 8/11/99. Baited with dried almonds collected from the orchard, weekly monitoring detected no ant activity.

Peach Twig Borer Shoot Strikes

Shoot strike monitoring began on 3/25/99 and continued weekly until 6/29/99. The first peach twig borer larva was found on 6/8/99. Preceding that, only oriental fruit moth larva were collected. At the end of the first generation, a more intensive sample was taken. No peach twig borer larvae were collected.

Tree Bands

Five Nonpareil trees were randomly selected in the same row where traps were placed. Corrugated cardboard was stapled around the trunks and the main scaffolds. These bands were to be monitored at the end of the peach twig borer generation for the presence of pupae. Upon returning to the orchard it was discovered that the bands were shredded by local wildlife. They were replaced but continued to be shredded on a weekly basis. No data was collected from tree bands.

Diseases

(shothole, scab, anthracnose)

Diseases were monitored by visual inspection and disease presence was to be reported immediately. There were no major disease outbreaks throughout the orchard this year.

Harvest

Harvest samples were collected from Nonpareil trees in the trap row on August 31, 1999. Five trees were chosen and 100 almonds collected totaling 500 almonds per block (2000 almonds from the orchard or twenty, 100 nut samples). Almonds were inspected for peach twig borer, navel orangeworm, oriental fruit moth and ant damage. Damage observed is expressed in percent in Table 5. Quality was outstanding in all four blocks this year.

Table 5. Harvest results from the Butte Co. Almond PMA site.

Results

The pest management program in this orchard has been implemented well. As of harvest, there is virtually no damage in any of the four treatment areas. However, in order to determine if there are differences in treatments, data must be collected for a number of seasons. We plan to continue this project in the same manner next year with little or no changes in procedure.

Butte County Almond PMA Satellite NOW Project

This is a replicated trial pertaining to the control of navel orangeworm. There are three replicated blocks of 20 acres each. Each block has 4 five-acre treatments. The treatments included hullsplit sprays of Lorsban, Success, Stealth, and a control. Shortly after the Stealth application, almonds were evaluated for the presence of navel orangeworm eggs and worms. One hundred almonds were sampled from one of the control blocks and also from each of two of the Stealth blocks on 8/3/99. Results from this initial evaluation are presented in Table 6.

Table 6. Percent of NOW in each treatment on 8/3/99.

Navel orangeworm traps were also placed in the middle of these 3 treatments and traps were checked weekly. On 9/9/99, five, one hundred nut samples were collected from each treatment in each block. Five Nonpareil trees were randomly selected from the center row in each plot. In a similar fashion a follow-up sample was collected from the Harvey variety on 9/17/99. At that time, two hundred nuts were collected from each treatment in each block. Almonds were evaluated for oriental fruit moth damage, navel orangeworm damage, peach twig borer damage, and ant damage. The results presented in the tables below reflect navel orangeworm damage only. Navel orangeworm harvest data is presented in Table 7 for the Nonpareil results and Table 8 for the Harvey results.

Table 7. NOW harvest damage of Nonpareil variety.

Table 8. NOW harvest damage of Harvey variety.

Results

The satellite project has produced an interesting trend in navel orangeworm control. There was very little damage at harvest in the Nonpareil variety in the treatments and the replicates, however, the damage of the Harvey variety is substantially higher. This project should be replicated again next season in order to adequately determine the best form of control for the navel orangeworm.

Plans for Year 2:

Both projects have been implemented quite effectively and thoroughly. We plan to continue for the following year with little or no modifications in protocol. A project that continues data collection and monitoring over the course of many seasons, will allow more insight to environmentally friendly means of pest control in California almonds.