| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00675 | |
| Title | Development and Integration of Pest Management Stategies for High Value Cropping Systems: Fruit and Vegetables |
| Investigator(s) | Zimmerman, RJ; |
| Department | Bioagricultural Sciences and Pest Mgmt. |
| Objectives | 1) This project will evaluate the effectiveness of trap crops at preventing the movement of beet leaf hopper, Circulifer tenellus (Baker)(Homoptera:Cicadellidae) into commercial tomato fields and the subsequent transmission of beet curly top virus. 2) The second project will be conducting experiments which will lead to the development and implementation of multi-tactic control programs for insect pests of fruits and vegetables. Several insects continue to be significant problems for growers, including codling moth, Cydia pomonella, western cherry fruit fly, Rhagoletis indifferens and European paper wasp, Polistes dominulus. |
| Approach | 1) Two species of trap crops, sugar beets and mustard, will be planted in strips adjacent to tomato plots. The trap crops will be treated with insecticides for control insecticides to kill leafhoppers before they can move into the tomatoes and transmit the beet curly top virus. The tomatoes and trap crops will be regularly sampled for leafhoppers. The tomatoes will also be assayed for beet curly top virus infection. 2) Insect pests continue to be a challenge for organic growers. Two insects, codling moth, Cydia pomonella and western cherry fruit fly, Rhagoletis indifferens, continue to be a challenge for organic growers. Codling moth trials will involve combinations of Trichogramma wasps, granulosis virus and spinosad. Western cherry fruit fly trials will involve the use of entomogenous nematodes, Heterorhabditis spp., for control of the pupal and adult stage. Experiments are planned which will attempt to distribute the nematodes via microsprinklers. The European paper wasp , Polistes dominulus, has emerged as significant pest for grapes and cherries. Investigations for control of this insect will involve different baits. |
| Keywords | trap crops, Beet curly top virus, codling moth, Cydia pomonella, western cherry fruit fly, Rhagoletis indifferens, European paper wasp, Polistes dominulus; |
| Progress Reports | |
| 1993 | Mating disruption for control of codling moth (CM) was evaluated in apple and pear blocks in western Colorado. A 2 ha apple block was treated with 2 applications of 162 Shin-et-su rope sex pheromone dispensers/ha (pre-bloom and prior to second flight of CM), plus 3 border sprays of azinphosmethyl (3.4 kg 50W/2837.5 l water/ha) and 2 border sprays of phosmet (6.8 kg 50W/2837.5 l water/ha). CM infestation at harvest was 3.9%, an adjacent 2 ha apple block (conventional pest management (21-day spray intervals of azinphosmethyl) had 1.9% CM infested fruit. A 1 ha pear block received a single pre-bloom application of 162 Shin-et-su rope dispensers/ha with the same border sprays as the apple block. The treated edge had 7.4% CM infested fruit, while the untreated center had 43.3% infested fruit. Another 2 ha pear block received 2 applications of 162 Shin-et-su rope dispensers/ha (pre-bloom and prior to second flight of CM). CM moth infestation was 0%. Imidacloprid, a new insecticide with a novel mode of action, was evaluated on green apple aphids at 47.32 mlFS/378 l water. This treatment was compared with endosulfan (340.2 g W/378 l water), a standard treatment for green apple aphids. In three field trials, imidacloprid and endosulfan treatments resulted in 100% mortality of treated green apple aphids. |
| 1994 | A 5ha apple block was treated with 1 application of 1000 Shin-et-su rope sex pheromone dispensers/ha-pre-bloom (SESRD). A single border spray of azinphosmethyl(1.7kg 50W/2837.5L water/ha) was applied 21 days after biofix. Codling moth(CM)infestation at harvest was 0.05%. A 2ha organic apple block was treated with 1 application of 1000 SESRD/ha-pre-bloom, in addition, 7 applications of Ryania, were applied over the summer. CM infestation exceeded 50%. A 2ha pear block received 1 application of 625 SESRD/ha-pre-bloom. Insecticides were not applied during growing season. CM moth infestation was 0%. Imidacloprid was evaluated on green apple aphids at two rates, 59ml and 29.5ml/378L water. This was compared with endosulfan(340 .2g WP/378L water). In the first trial, all treatments were applied at 1890L. Mortality ranged from 40 to 73% for treatments. The remaining two trials were applied 2835L/ha. Mortality in both trials exceeded 99% for all treatments. Trichogramma platneri (Hymenoptera:Trichogrammatidae) was released weekly for 4 weeks for control of second generation CM. Three rates were released per semi-dwarf apple tree: 250, 500 & 1000 wasps. There was no difference between control trees(no wasps) and trees with wasps. There was no significant differences in rates of CM infestation between wasp release rates. A release cage designed from PVC pipe provided protection for pupating T. platneri and reduced time for placing wasp in the field. |
| 1995 | Growers cooperated in a pest management program in which no insecticides were applied to apples after bloom. Mating disruption via a single application of 1000 Shinet-su rope sex pheromone dispensers/ha on 28.4 ha. Codling moth (CM) infested fruit totaled 2.28%. Secondary pests were kept in check by natural enemy activity. Horticultural oil (Orchex) was evaluated in two apple orchards for the control of CM. Horticultural oil was applied at 15ml/1L water (458 L water/ha every 2 weeks starting 200 degree days from biofix. Orchard 1 consisted of 1 .01 ha of the variety Winesap and had 1.67% CM damage. Orchard 2 consisted of 2.02 ha of the varieties Jonathon and Rome and had 17.7% and 7.7% CM damage, respectively. The egg parasite, Trichogramma platneri, was released at three different rates; 4000, 2000 and 1500 wasps/apple tree) for control of the CM. The trees were 10 years old (ave 2.7m in ht, 3m x 6.1m spacing). There was 12 repetitions per rate (a single tree equaled one repetition). The wasps were released weekly starting 7 days after biofix. The amount of CM damaged apples was not significantly different than that found in the control and there was no significant differences between the rates. Field trials were conducted to evaluate azadirachtrin-based formulations for the control of green apple aphids, Aphis pomi. |
| 1996 | Codling moth control was attempted with summer oil applications and a growth regulator. Horticultural oil (Orchex) was evaluated on twenty acres of mixed apple varieties. Horticultural oil was applied at a concentration of 15 ml/1 L water (458 L water/ha) approximately every two weeks starting in July. A first cover spray of azinphosmethyl was applied 200 Degree Days after biofix. Due to inconsistencies in applications (applications were not on a consistent 2 week basis and were normally made in the heat of the day), yellow skinned apples were not commercially acceptable due to enlarged lenticels and excessive surface blemishes. Codling moth infestations in red skinned apples exceeded 30 %. An insect growth regulator (tebufenozide) (4.8 oz/100 gal) was compared with azinphosmethyl and phosdrin for codling moth control. There were no significant differences between the treatments and the control. Alyssum, blackfoot daisy, white dill, tansy phacelia and buckwheat were evaluated for inclusion into a habitat management program as nectar and pollen sources. Each plant species was replicated in 4 - 6 ft X 12 ft plots. All plants were either seeded or planted from transplants at the end of May. Buckwheat and tansy phacelia produced the most flowers and attracted the highest number of predators and parasites. |
| 1997 | Pheromone puffers (releases sex pheromone of Cydia pomonella) were evaluated in two blocks in western Colorado. Block 1 (3.7 h) is mature standard sized apple trees. This block consisted of 3 varieties of apples: Jonathon, Golden Delicious and Rome. This block and surrounding blocks have been under mating disruption for the previous 4 yrs using Isomate-C phero. dispensers. Puffers were placed equidistantly on the perimeter for the equivalent of 10 puffers/h on April 29, 1997. Puffers were placed in the upper 1/3 of the tree. Each puffer held 1 aerosol can of 17.25 gms of codlemone (= 170 gms of phero./h = 10 puffers/h). Each puffer emits a blast of pheromone every 25 min. (57.6 times/day,= 216 mg of codlemone per day) . One application of Guthion was applied for first codling moth (CM) generation. Block 2 (20 mi w of block 1) consisted of 4.05 h of mature standard Golden Delicious and Red Delicious apple trees. Mating disruption has never been used in this block. Puffers were placed equidistantly on the perimeter for the equivalent of 5 puffers/h on May 2. Each puffer held one aerosol can containing 34.5 gms of codlemone (= 170 gms of pheromone/h = 5 puffers/h). Each puffer emits a blast of pheromone every 25 minutes (57.6 times/day,= 432 mg of codlemone/day) . This orchard was on a standard control program (every 21 days with azinphosmethyl). Puffer efficacy in both blocks was determined by: a) percent CM infestation at the end of the season, and b) phero. trap catches. Results- Block 1: Apples were evaluated for CM infestation on September 15. 50 fruit were randomly selected from 30 trees. 10 trees were chosen from the west side, middle and east side of the block. Infestation was 0.8% (middle), 1.2% (western edge) and 4.6% (eastern edge). The total number of fruit sampled was 1500 with the overall infestation of 2.2%. The 1997 codling moth trap catches for this block was compared with the trap catches for 1995 and 1996. 4 traps using 10X lures were used for each year. In 1995 and 1996 Isomate-C ph |
| 1998 | Mating disruption for the control of codling moth is used successfuly on more than 50% of the apple producing acres in Colorado. Current technology requires the placement of individual ties in trees (400 per acre) to maintain pheromone presence throughout the orchard canopy. An obstacle to the use of pheromone ties is the cost of labor for application. Over the last two years a mechanical device (called a puffer) has been evaluated in apple blocks. The device releases bursts of pheromone from an aerosol at pre-set times over a 24 hour period. On May 19 , 1998, 12 puffers were placed on the perimeter of a 5 acre block (553 ft [E-W] x 320 ft) of high density apples (14ft x 5 ft). The puffers were spaced every 60 feet (4 puffers) on the east and west edge of the block (the wind moves east to west pattern in the am and west to east in the pm). Two puffers were place on the south and north edge of the block, 150 feet from each edge. In addition, 3 puffers were equally spaced through the middle of the block (north-south line). The timers were set to release pheromone every 20 minutes for the entire growing season. Each puffer released 7.5 mg of codling moth pheromone per burst. This the equivalent of 540 mg/puffer/day. Approximately 168 gms of pheromone was released per acre. The 5 acre block was divided into 12 plots for evaluation. Infestation ranged from 0 to 14.4%. The highest infestations were found on the east and southeast side of the block, which was adjacent to an experimental block of apples which had over 50% infestation. |
| 1999 | The increased use of mating disruption for the control of codling moth, Cydia pomonella, has resulted in a corresponding increase of oblique-banded leafroller (OBLR) damage in apples. The purpose of this study is to determine the impact of OBLR, Choristoneura rosaceana (Harris), sex pheromone on adult and larval populations. In June 1999, three different types of experimental oblique-banded leafroller pheromone dispensers (Shin-et-Su Corp.) were placed into three, 20 acre apple blocks in Western Colorado.These apple blocks were located on Rogers Mesa, west of Hotchkiss. The pheromone dispensers were: a) twin dispenser (220 mg oblique-banded leafroller sex pheromone [OBLR] and 220 mg codling moth sex pheromone, b) 80 mg OBLR sex pheromone dispenser and c) 250 mg OBLR sex pheromone dispenser. The dispensers were placed in the orchards at the following rates: a) 80 mg dispensers - 400/acre, b) 250 mg dispensers - 200/acre and c) twin tube dispenser - 200/acre. The following blocks received the pheromone dispensers: a) twin tube dispenser - Silver Spruce Orchards, dispensers split between standard size Romes and semi-dwarf Golden Delicious, b) 250 mg dispenser- Eastman/Phillips orchards, dispensers were placed into standard sized Golden Delicious, Gala and Jonathan apple trees and c) 80 mg dispenser- First Fruit Orchards, dispensers were placed into standard sized Golden Delicious trees and semi-dwarf Galas. Adult and larval OBLR populations were monitored throughout the summer. Adult populations were monitored using delta-wing pheromone traps. Traps were monitored weekly by a scout employed by the Codling Moth Areawide Management Program (CAMP). Larval populations were measured on three dates: June 24, July 30 and August 23. Fruit and leaf clusters were sampled from the upper part of the apple trees using a telescoping pruning shear. On each sample date, 30 samples were taken in a random pattern from the upper third of the tree canopy. Larval sampling was also conducted in organic orchards which did not employ OBLR pheromone disrupters. OBLR larvae were not detected in any of the orchards on any single sampling date. Pheromone trap catches were significantly reduced in the mating disruption blocks (season totals for 6 traps in mating disruption blocks- 0, 0, 1, 1, 3, and 4). The number of adult moths was significantly less in 1999 when compared with trap catches for similar dates in 1998 and total numbers for both growing seasons. OBLR trap catches in nearby apple blocks which did not employ mating disruption were significantly higher than those blocks using mating disruption (season totals for 6 traps in nearby non-mating disruption blocks- 141, 483, 557, 331, 345, and 345). Trap catches in non-mating disruption blocks in all apple blocks in the immediate area (approximately 1200 acres of fruit) averaged 282 moths (35 traps). Monitoring will continue in the spring of 2000 to determine populations of OBLR larvae in apple blocks employing mating disruption or standard programs. |
| 2000 | European earwigs have become an important pest in organic peaches. Damage can exceed over 50%. European earwig, Forficula auricularia, populations have been monitored for the last two years in two organic peach orchards. This study was initiated to answer the following questions: 1) what is the source of the high numberof earwigs found in the peaches, when do the earwigs move into the peach orchards and is there an effective organic control for earwigs? The highest earwig populations are found in adjacent apple orchards. There has been no reported damage to apples as a result of earwig feeding. Areas of dense plant growth such as found bordering the canal bank alongside the peach orchards were found to harbor large populations of earwigs. The higher numbers of earwigs were found in the apple orchards. Plant species and plant density are similar in both the apple blocks and peach blocks at both locations. However, apple blocks may harbor a greater number and variety of insect prey. Earwigs were found feeding on codling moth larvae. The highest number of earwigs were found in the peach orchards as the peaches ripened. This increase in numbers of earwigs in the orchard may be due to volatiles emitted from the ripening peaches. The numbers in the apple orchards remained high from mid-summer through the end of the survey. Control of earwigs through trapping would probably not be an option due to labor costs and the large number of traps which would be required to impact the earwig populations. Virtually all of Colorado peaches are sold on the fresh market. Because of fresh market sales and the demand for high quality fruit there is no tolerance for insect damage, especially the large gauges in the peach created by earwig feeding. One attempt at preventing earwigs from moving into the peach trees is a sticky barrier. A band of Tanglefoot, a sticky substance, is spread around the trunk of the peach tree. Usually the Tanglefoot is spread over a plastic wrap which is tightly wound around the tree trunk. The bands were 30 cm or greater in width. Despite the bands earwigs were still found in the trees. In 1999, the bands were found to reduce the number of earwigs in the tree by 50% compared to trees which were not banded. Earwigs may be gaining access into the canopy by flying. Other researchers have noted that earwigs can fly. Three different organic sprays have been evaluated over the last two years: azadirachtrin, pyrellin and spinosad. Both Azadirachtrin and Pyrellin were ineffective at controlling earwigs. However, in two laboratory feeding trials, spinosad at the equivalent rate of 147.5 ml/378.5 L water, caused 100% mortality among earwigs after 72 hours. At 24 hours, the earwigs were observed to have ceased feeding and were laying on their dorsal side with some movement. Feeding was observed, but only very small amounts of the food source were removed. Field trials with the spinosad were not performed. |
| 2001 | In organic orchards, growers are facing two important management problems, weed control and soil fertility. Progressive organic growers are using permeable landscape cloth for weed control in tree rows. A disadvantage to landscape cloth may be the inhibition of incorporation of organic matter and nutrients into the soil. This may lead to negative effects on soil biota , consequently effecting nutrient cycling in the orchard ecosystem. Soil fertility is typically augmented with compost or chicken manure. However, two obstacles may bar the future use of compost and/or manures: cost of material and the potential for fruit to be contaminated with E. coli. In order to address these two related problems, a project was initiated to examine the effects of weed mat and two different green manures on soil microbial and soil microarthropod community structure and functioning in organically managed peach orchards. The research has been implemented into newly planted peach blocks. These sites are at two locations chosen for their differences in climate and soils. The green manures planted are alfalfa and sheep fescue. In the summer of 2001, fungal, bacterial, protozoan and microarthropod populations were sampled every 30 days. In the late fall of 2001, litter bags were place in the plots to measure the rate of decomposition of the green manures in the different treatments. In the summer of 2002, nematode and earth worm populations will be sampled in addition to the other faunal groups. The results of 2001 sampling will be available in the spring of 2002. |
| 2002 | Fruit pest management programs are currently in transition. Insect pest management programs are transitioning from organophospate and carbamate insecticides to programs utilizing narrow-spectrum insecticides and/or organic controls. In recent years, there have been many narrow-spectrum (i.e. insect growth regulators) and organic insecticides introduced to the marketplace. However, product efficacy is many times dependent on local climatic conditions. In western Colorado, high UV light levels and low humidity have been observed to have significant impacts upon efficacy levels when compared with trials conducted in other areas of the United States. This research is designed to determine whether new insecticides are efficacious under Colorado climatic conditions and if there is a fit into local fruit pest management programs.This project compared the efficacy of three types of insecticides on pear psylla, Cacopsylla pyricola: 1) an insect growth regulator (pyriproxyfen, 5 oz per ac), 2) an organophospate (endosulfan, 21 oz per ac) and 3) an organic clay based insecticide (kaolin, 25 lbs per ac). All treatments were applied in mid-May to mature Bartlett pear trees located near Grand Junction, Colorado. Pear psylla counts were taken prior to treatment followed by evaluations at 7, 14 and 45 days after treatment. All treatments had significantly lower pear psylla adults than the control at 7 and 14 days after treatment. The endosulfan and kaolin treated trees had significantly lower numbers of pear psylla than the those trees treated with the pyriproxyfen after 7 days. At day 14 and day 45 there were no differences in pear psylla numbers among all treatments. At day 45, there were no differences between the control and the treatments. However, in the control block, significant amounts of honeydew could be observed on fruit and leaves. Honeydew deposits were not found in trees treated with the three test compounds. Growers will most likely not adapt the use of kaolin for control of pear psylla. In wet years, multiple applications of kaolin may need to be applied as it washes off in the rain . Fruit packers are also finding that kaolin is difficult to wash completely off the fruit, leaving a dull film on the fruit surface. The pyriproxyfen demonstrated control of pear psylla equal to that achieved by the endosulfan. |
| 2003 | Weed control without the use of synthetic herbicides is an expensive and time consuming task in perennial organic/sustainable agricultural systems. Orchardists have few non-synthetic options available for weed control. A few naturally derived herbicides are commercially available, but they have biological and economical disadvantages for commercial growers. Currently, orchardists are employing two types of physical weed control; permeable landscape cloth and mechanical cultivation using devices such as weed badgers, Clement's hoe or flamers. This project is designed to compare two types of of thermal weeders: direct flame and infrared radiant heat. Both methods rely on propane combustion to generate heat. The infrared radiant heater is a prototype machine which is not currently available to growers. Both types of flamers were evaluated at 3 different speeds (1, 1.5 and 2 mph) and at two different treatment intervals, every 2 or 3 weeks. The experiment was started in late May and continued through mid-August. Each treatment was replicated 6 times. Each treatment was 30 feet long. Weed cover was measured at the beginning of the experiment and at the end of the experiment. The direct flamer was significantly more effective at reducing weed cover than the infrared radiant heat at all speeds and treatment intervals. Weed cover in the direct flame averaged 6.2% (1 mph), 18.9% (1.5mph) and 7.7%(2mph) in plots treated every 2 weeks. Weed cover in the infrared radiant heat plots averaged 51.9% (1mph), 54.3% (1.5mph) and 52% (2mph) in plots treated every 2 weeks. There was no significant difference in weed cover when the treatment interval was increased to 3 weeks when using the infrared radiant heat. However, increasing the treatment interval from two to 3 weeks resulted in a significant increase in weed cover in the direct flame plots at 1 mph (23.7% weed cover) and 2 mph (20% weed cover. |
| 2004 | There has been a significant decline in the number of acres devoted to fruit production in western Colorado. However, there has been an increase in vegetable production. Accompanying the increase in vegetable production has been a greater interest in organic and soft pest management tactics. The objective of this study was to evaluate the efficacy of biological and narrow spectrum insecticides against the lepidopteran pest complex found on broccoli in western Colorado. This trial was conducted at the Western Colorado Research Center- Rogers Mesa Site, located near Hotchkiss, Colorado. The elevation is approximately 5800 feet and the growing season averages 150 days. Broccoli transplants, Brassica oleracea, were planted on May 19, 2004. The transplants were planted into white plastic mulch on 0.6m in-row spacing. Irrigation water was applied by drip irrigation and fertilizers were applied with an injection system. The plot sizes were 4.8m X 10m. The treatments were arranged in a randomized complete block design. Each treatment was replicated 4 times. Treatments were applied on June 28, July 8 and July 16. 10 plants from each plot were sampled prior to the first treatment, and 4 days after the July 8 and July 16 treatment. Ten plants were sampled at each sample date from each plot. The larvae collected were cabbage looper, Trichoplusia ni, diamond back moth larvae, Plutella xylostella and imported cabbageworm, Pieris rapae. Treatments were applied with a CO2 operated back pack sprayer operated at 21 psi. There were nine treatments : 1) Xentari 10.3WD, (8 oz product/ac, Valent Corp.) and S-1812 35 WP (0.15lb a.i./ ac, [a.i. pyridalyl] Valent Corp.), 2) V-10132 2.58 EC (6 oz a.i./ac,[ pyridalyl and esfenvalerate,a.i.] Valent Corp.), 3) V-10132 2.58 EC (9 oz a.i./ac), 4) V-10132 2.58 EC (12 oz a.i./ac), 5) Dipel 6.4 WP ( a.i. Bacillus thuringiensis var. kurstaki, Valent Corp.) and S-1812 35 WP (0.15lb a.i./ ac), 6) S-1812 35 WP (0.15lb a.i./ ac), 7) S-1812 35 WP (0.20lb a.i./ ac) and a control. Results: There were no significant differences between the treatments. However, all treatments had significantly lower worm numbers than the control. The European paper wasp, Polistes dominulus , a recently introduced predator, may have confounded the results of the trial. Large numbers of the wasps were observed hunting for lepidopteran larvae in the broccoli plots during the season. A population count of the wasps was not taken, but often 2 or more wasps could be observed at a time hunting worm larvae on a single broccoli plant. Several parasitic insects were collected from the plots including Voria ruralis (Tachinidae:Diptera), Copidosoma truncatellum (Encyrtidae:Hymenoptera) and Hyposoter exiguae (Ichneumonidae:Hymenoptera). |
| 2005 | The objective of this study was to evaluate the efficacy of Vydate L and Lannate LV applied via drip irrigation for the control of onion thrips, Thrips tabaci. This trial was conducted at the Western Colorado Research Center- Orchard Mesa Site, located near Grand Junction, Colorado. Queen-Gil Drip tape (10.1 cm emitter spacing, 81.2 lph/30.4 m,11 psi) was placed approximately 5.1 cm below the soil surface down the middle of each bed. Each bed was 76.2 cm wide. Four rows of onions (A. cepa L. var. Flare) were seeded down the length of each bed. The size of the onion planting was 12.2 m x 53.3 m. There were 6 replications per treatment. Each replicated plot was 76.2 cm inches x 22.9 m. The onions were seeded on April 14, 2005. The plants were planted into white plastic mulch on 0.6m spacing. The treatments were arranged in a randomized complete block design. Treatments were as follows: a) Vydate L (7 day application interval, 0.95 l/ac/application) June 24 , July 1, July 8, July 15, July 22, b) Vydate L (14 day application interval, 1.9 l/ac/application) June 24 July 8, July 22, and c) Lannate LV (7 day application interval, 0.71 l/ac/application) June 24 , July 1, July 8, July 15, July 22. All treatments were applied through the drip lines. The pH of the application solution was made neutral through the addition of phosphoric acid. After each treatment was injected, the lines were allowed to run for 15 minutes to flush out residual insecticide and to move insecticide into the plot. After the last treatment, all lines were opened and irrigation proceeded until the onion beds were wet across the bed. Sample dates were June 30, July 7, July 14, July 21 and July 28. Five onion plants were sampled per plot on each sampling date. The onion plants were placed in a Berlese funnel for 24 hours to extract the thrips. Results: There were no significant differences in number of adult onion thrips and thrips nymphs on the same sample date between treatments. There were significant differences across sample dates for the same treatments. Vydate L (14 day treatment), Lannate LV and Control all had significantly more onion thrips adults on the July 7 sample date. Nymphal counts appeared to peak on the July 14 sample date. There were no significant differences between treatments in regards to onion size and percentage of onions in a particular size class (colossal, large or medium). Overall, onion thrips counts were low. Stand quality may have been influenced by high weed pressure, despite two applications of herbicide and regular hand weeding. Onion thrips populations may have also been low due to the lack of nearby commercial onion production. |
| 2006 | Six insecticides were applied to onions to evaluate efficacy against onion thrips, Thrips tabaci. Three methods were used: drip, foliar and side dress. Treatments applied via drip were Vydate L (4.7 l/ha), and Lannate LV (0.6l/ha). Treatments applied foliarly were Vydate L (4.7 l/ha), Lannate LV (0.6l/ha) and Carzol(0.45kg product/ha). Vydate L (7 l/ha) was applied as a side dress. There were 4 replications per treatment. Each plot was 3m by 7.6m. The treatments were randomized within the 4 blocks. Each block contained 6 treatments plus a control. All treatments were irrigated via subsurface drip lines. Each plot consisted of three 12cm wide beds with a single drip line down the center of each bed. Onions were planted on May 15 in rows 5cm and 15 cm on each side of the drip line for a total of 4 rows per bed. Seeding rate was 217,500 seeds/ha. Emitters were spaced every 10cm. Flow rate was 243LPH/25 .4m or 4.2LPM/25.4m. A 5cm pressure reducer valve was used to reduce the pressure of water entering the drip lines to 9 PSI. The onions were irrigated once per week for approximately 6 hrs per irrigation episode. Insecticides were injected into the drip lines using an electromagnetic dosing pump. All application solutions were buffered using phosphoric acid. Starting pH of application solution ranged from 6.85 to 7.0. Approximately 5ml of phosphoric acid added to 11.4l of the application solution was needed to bring pH to a range of 4-5. Each drip application took approximately 40 minutes. An application of glyphosphate herbicide (3% solution) was applied on May 23. This was followed up by an application of the herbicide, Buctril (Bayer Corp.) at 0.6l/ha on June 19 and an application of the herbicide, Starane (Dow Corp.)at 0.6l/ha on June 21. The plots were hand weeded on July 21 and August 22. Treatments began on June 26. Onions were sampled 0, 3 and 7 days after application. Applications were made on June 26, July 11 and July 24. On each sample date 5 onion plants were randomly selected from each plot and placed in a marked 1 gal plastic bag. The onion thrips were extracted from the onions using Berlese funnels. The onion plants were kept in the Berlese funnels for 24 hours. Results: Onion seed germination was severely impacted in the plots due to crusting caused by a rainfall incident of 0.89 cm on May 19. Despite multiple herbicide sprays and hand-weeding the plots, weed pressure was heavy throughout the plantings during the course of the growing season. Overall, the onion stand and quality was poor. This may have affected the results of the project. Onion thrips pressure was moderate throughout the season. Onion thrips populations did not significantly start to increase until mid-July. This may have been due to the late planting of the onions and weed pressure masking the presence of the onions. Those treatments which had significantly lower populations of thrips than the control throughout the season were Vydate L (drip applied), Vydate L (foliar), Lannate (foliar) and the Carzol (foliar). Those plots in which the Vydate was side dressed showed considerable variability, having populations similar to those sampled in the control. |
| Impact | |
| 1999 | Successful control of oblique-banded leafroller with mating disruption will lead to a significant decrease in the use of neurotoxins in fruit pest managment in Western Colorado orchards. |
| 2000 | Knowledge of the ecology and biology of earwigs has helped growers to define the optimum window for controlling earwig populations in organic peaches. Growers need to concentrate their control efforts within a few days of harvest as earwig populations are at very low numbers prior to harvest. Also, the traditional control tactic of banding trees with a sticky substance to prevent earwig movement into the trees, was found to be ineffective. In laboratory trials, spinosyn showed promise as a control for earwigs. |
| 2001 | This research is critical to organic fruit growers of Colorado and other fruit growing regions in the west. The elucidation of the interactions of novel weed control tactics such as landscape cloth and soil fertility management options such as green manures on the soil food web may give growers the tools to decrease external inputs. The ultimate goal of this research is to provide baseline data from which growers and researchers may further develop methods for manipulation of soil fauna to maximize nutrient cycling which mitigates the impact of agriculture on the environment. |
| 2002 | This research project will have a significant economic impact for fruit growers. First of all, this research has identified two environmentally-compatible control alternatives to endosulfan for western Colorado pear producers. Secondly, due to the specificity of pyriproxyen, natural enemies such as spiders, parasitic wasps and other general predators were able to thrive in the pear orchard. The conservation of natural enemies allows for a greater utilization of biocontrol and less dependency on chemical control. The third significant finding is that kaolin will not have a fit in local pear pest management programs. This fit is not due to adequate insect control, but rather the negative impact on fruit appearance and the potential for multiple applications due to rain. The utilization of insect growth regulators, such as pyriproxyen, gives growers the confidence to make the first steps towards a biological-based pest management program. |
| 2003 | This research will give organic and conventional orchardists non-chemical options in weed control. The infrared radiant heat is safer than the direct flamer. The operator is not exposed to direct flames from the propane. Also, there is reduced opportunity for uncontrolled fires in the orchard understory. |
| 2004 | This research is part of a larger effort to assist small acreage farmers in developing organic and/or biorational pest management programs for a wide variety of crops. Mountain valleys such as the North Fork Valley of the Gunnison River are increasingly gaining statewide and national recognition for fruit and vegetable production. The area is especially recognized for organic production. Research such as the broccoli trial gives growers information that is applicable at a local level. |
| 2005 | The use of drip irrigation in onion production is increasing in western Colorado. The application of insecticides through the drip system has many economic and environmental advantages for growers. Insecticide application directly to the root zone of the plant reduces the opportunity for run-off or spray drift and a decrease in the amount of insecticide applied per acre. Growers can potentially increase their profitability by spending less tractor time in the field for onion thrips treatment. They may also realize savings because by using less insecticides. |
| 2006 | The use of drip irrigation in onion production is increasing in western Colorado. The application of insecticides through the drip system has many economic and environmental advantages for growers. Insecticide application directly to the root zone of the plant reduces the opportunity for run-off or spray drift and a decrease in the amount of insecticide applied per acre. Growers can potentially increase their profitability by spending less tractor time in the field for onion thrips treatment. They may also realize savings because they use fewer insecticide applications. |
| Publications | |
| 1993 |
LARSEN, H. J., GAUS, A. G. & ZIMMERMAN, R. J. 1993. (Update). Colorado Tree Fruits: 1993/1994 Pest & Crop Management Guide. Bul XCM-41. Colo. State Univ. Coop. Ext. ZIMMERMAN, R. J. 1993. Some Biological Alternatives in Pest Management. Proc. W. Colo. Hort. Soc. Jan. 19-21, Grand Junction, CO. |
| 1994 |
CRANSHAW, W. S. and ZIMMERMAN, R. J. 1994. Insect Control with Insect Parasitic Nematodes. Service In Action. Colo. State Univ. Coop. Ext. Bul 5.573. ZIMMERMAN, R. J. 1994. Imidacloprid, a New Insecticide for Apples. Fruit Growers Newsletter. 14(6). ZIMMERMAN, R. J. 1994. Life Cycle and Management of the Codling Moth, Cydia pomonella. Fruit Growers Meeting, Spring. Hotchkiss & Clifton, CO (Unpub.) ZIMMERMAN, R. J. 1994. Mating Disruption in Western Colorado Apple and Pear Orchards. Western Colorado Horticultural Society Annual Meeting. Grand Junction, CO. |
| 1995 |
Magloire, Francine. 1995. Integrated Pest Management in Apple Orchard Systems in Western Colorado. M.S. Thesis. Dept. of Entomology, Colo. State Univ., Fort Collins Zimmerman, R.J. 1995. Organic Pest Management in Western Colorado Apple Orchards. Jan. 17. Western Colorado Horticultural Convention, Grand Junction, Colorado Zimmerman, R.J., D. Casey Sclar, T. Randolph and W.S. Cranshaw. 1995. Toxicity of neem-derived insecticides to various life stages of the elm leaf beetle. J. Arboriculture 21(4):181-186 Zimmerman, R.J., E. Nelson and B. Kondratieff. 1995. Grape Leafhopper Study 1995, Part I. Fruit Growers Newsletter. 15(2):1-2 Zimmerman, R.J., E. Nelson and B. Kondratieff. 1995. Grape Leafhopper Study 1995, Part II. Fruit Growers Newsletter. 15(3):1-2 |
| 1996 |
Zimmerman, R.J., B. Kondratieff, E. Nelson, and C. Sclar. 1996. The Life History of Two Species of Grape Leafhoppers on Wine Grapes in Western Colorado. J. Kansas Entomol. Soc. 69(4):337-345 |
| 2000 |
Zimmerman, R. J. 2000. Chemical control of codling moth, Cydia pomonella, in apples. Western Colorado Research Center Research Report. Agricultural Experiment Station Technical Report. TR00-4. |
| 2001 |
Davis, J.G., R. Zimmerman, K.V. Iversen and A. Gaus. 2001. Nutrient availability for apple trees from chicken manure and compost. In Agronomy Abstracts. Amer. Soc. Agronomy/Crop Sc. Soc . Amer./ Soil Soc.Amer. National Meetings, Charlotte, NC; Oct. 21-25, 2001. Doles, J. L., R.J. Zimmerman and J.C. Moore. 2001. Soil Microarthropod community structure and dynamics in organic and conventionally managed apple orchards in Western Colorado, USA. Applied Soil Ecology 18:83-96. |
| 2002 |
Alam, M. and R. Zimmerman. 2002. Subsurface Drip Irrigation and Plastic Mulch Effects on Yield and Brix Levels of Kabocha Squash, Cucurbita moschata. Understanding & Addressing Concervation and Recycled Water Irrigation. 2002 Conference Proceedings-The Irrigation Association. Pp. 2-8 The Irrigation Association, Falls Church, VA. |
| 2004 |
Alam, A. and R. Zimmerman. 2003. PLastic mulch and subsurface drip irrigation effects on yield and brix levels of kabocha squash. International Water and Irrigation 23(2):37-41. |
| 2005 |
Alum, A. and Zimmerman, R. 2003. Plastic mulch and drip irrigation effects on Kabocha squash yield and soluble solids content. Pp. 370-375. In, Water-Saving Agriculture and Susainable Use of Water and land Resources, Shaozhong, K., B. Davies, L. Shan and H. Cai, [Eds.]. Shaanxi Science and Technology Press, Shangai, China. Zimmerman, R.J. 2005. Evaluation of two methods of thermal weed control in fruit tree orchards . Report to the Environmental Protection Agency-Region 8. Pesticide Special Project X988708-1. (Unpub.) |