Backpack Mistblower Research Articles

Relative efficiencies of experimental and conventional foliar sprayers and assessment of optimal LWA spray volumes in trellised wine grapes.

Leaf wall area (LWA) has been proposed as an appropriate dose expression for field testing of plant protection products (PPPs) applied via foliar spray in trellised grapes. However, its efficiency could change depending on the characteristics of the crop or the pesticide application equipment (PAE). Herein, three spray technologies were evaluated. A traditional air-assisted tractor-mounted sprayer was compared with two portable knapsack sprayers: a backpack mistblower and a backpack hydraulic sprayer. Trials were conducted in trellised wine grapes at three selected crop stages (BBCH 55, 65, 75) covering the main period of canopy development. In each canopy stage, leaf deposition and coverage were sampled for each technology. The tractor-mounted sprayer was working at 200 L ha-1 of LWA spray volume for the earliest stage and 370 L ha-1 for the other two. Three higher volume rates were used for backpack sprayers up to 800 and 1250 L ha-1 for the mistblower and the hydraulic system, respectively. Optimal LWA spray volumes differed among application devices in terms of efficiency and uniformity of deposition on the canopy. The efficiency of each spray application also was conditioned by the spray volume. LWA is useful for defining optimal spray volumes in trellised grapes. However, both canopy density and spray technology should be considered to assist this process. Field testing of PPPs and subsequent label recommendations should consider the relative efficiencies of corresponding experimental and conventional spray technologies. © 2021 Society of Chemical Industry.

Optimization of Motorized Backpack Mistblower for Efficient Application of Insecticides against the Bagworm, Metisa plana Walker

Optimization of Motorized Backpack Mistblower for Efficient Application of Insecticides against the Bagworm, Metisa plana Walker

English

Experiments were conducted in season 2014B at Naivasha maize lethal necrosis screening facility to evaluate Tanzanian maize germplasms for resistance to maize lethal necrosis (MLN). One hundred and fifty-two maize landraces and 33 inbreed lines were artificially inoculated with maize chlorotic mottle virus and sugarcane mosaic virus isolates in two trials arranged in a completely randomized design (CRD) and two replications. Inocula for both virus isolates were prepared, combined and applied to the trials by a 12 L backpack mist blower 4 and 5 weeks after planting. Disease incidence was assessed based on a 1 to 5 MLN rating scale 14, 28, 42 and 72 days post inoculation (dpi) for landraces and 7, 14, 21 and 52 dpi for inbred lines. Significant phenotypic variations (P 0.05) were detected on inbreed lines as all materials were susceptible to MLN with scores ranging from 4.5 to 5 except for resistant check CML494 (mean score of 3.75). In this study, five maize landraces were identified as tolerant candidates against MLN. The identified landraces should be subjected to further MLN testing to explore their potential in breeding for MLN resistance. Key words: Zea mays, maize chlorotic mottle virus, sugarcane mosaic virus, maize lethal necrosis, maize landraces.

SR450 And Superhawk XP Applications Of Bacillus thuringiensis israelensis Against Culex quinquefasciatus.

Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) against Culex quinquefasciatus. Bacillus thuringiensis israelensis was applied at maximum label rate in a 232.26-m(2) field plot located in north-central Florida with containers placed at 2 heights (ground level and 1.52m above ground) on stakes positioned 3.04, 6.09, 9.14, 12.19, and 15.24m from the spray line. Results indicated that there was no significant (P > 0.05) difference in 24- and 48-h larval mortality between the 2 sprayers or between the 2 heights. There was significant difference (P < 0.05) among the 5 rows, with mortality continuously decreasing with increasing distance from sprayer. Both sprayers provided on average >70% larval mortality 3.04-9.14m from the spray line, and <60% mortality at 12.19 and 15.24m. The data suggest that the SR450 and Superhawk XP may be comparable sprayers for use with Bti to control mosquito larvae.

Improving the Composition of Beech-Dominated Northern Hardwood Understories in Northern Maine

Abstract The natural regeneration that develops following the shelterwood and selection harvesting of northern hardwood stands across the Northeast is often plagued by an overabundance of American beech infected with beech bark disease. This regenerating beech typically dominates and interferes with the regeneration of more desired hardwood species (sugar maple, yellow birch, and red maple), lowering the productivity and value of future stands. We tested factorial combinations of glyphosate herbicide (Accord Concentrate) rate and surfactant (Entrée 5735) concentration to identify an optimal treatment that would maximize beech control while minimizing sugar maple injury. Third-year posttreatment results revealed that glyphosate rate was a more important factor than surfactant concentration in reducing beech abundance and preserving sugar maple. The optimal treatment (0.56‐1.12 kg/ha of glyphosate plus 0.25‐0.5% surfactant) selectively removed 60‐80% of beech stems, whereas sugar maple control was less than 20%. The five dominant hardwood species differed substantially in their susceptibility to the treatments in the following decreasing order: beech &gt; striped maple &gt; yellow birch &gt; red maple &gt; sugar maple. Similar results produced using a backpack mistblower suggested transferability of treatment effects to operational applications using a tractor-mounted mistblower. Our findings indicate that this relatively low-cost and effective treatment can substantially improve the understory composition of northern hardwood stands.

SPRAY SPECTRA, DEPOSITION AND SEDIMENTATION CHARACTERISTICS FOR LOW PRESSURE LIQUID ATOMIZERS

The focus of this investigation was on assessing the feasibility of the evaluation new developing nozzles that will target and spray the biological pest control materials and herbicides. As well as comparing the spray characteristics for external mixing twin fluid nozzles with the low liquid atomizers motorized Backpack mistblower and ProptecTM rotary atomizer. The Stihl SR 340 Powerful knapsack Mist-blower 2.6 kW, rotary atomizer, Ledebuhr Industries, Inc. 11429 Upton Road Bath, Michigan-48808) and five developed an external mixing twin fluid (EMTF) nozzles were tested under laboratory condition to measure the spray droplet spectra, the spray deposition and sedimentation. Droplet size spectra produced by three atomizers, mistblower, rotary cage and EMTF nozzles were measured using the Malvern laser (particle size analyzer). The three atomizers were tested at flow-rate 0.5 l min -1and 1 l min -1. As well as, the motorized Backpack Mistblower and ProptecTM rotary cage atomizer were tested under four levels for rotational speed. The rotational speeds for ProptecTM Rotary cage atomizer were 3000 r.p.m, 3500 r.p.m 4600r.p.m and 5000 r.p.m; and its were 3000 r.p.m, 4000 r.p.m, 5000 r.p.m and 6000 r.p.m for Backpack Mistblower. On the other hand, the five EMTF nozzles were tested at 150 kPa air pressure. The three atomizers was operated at low various pressures, five external twin-fluid nozzles at 30 kPa , mistblower at 28 kPa and rotary atomizer at 90 kPa liquid pressures. The different atomizers were compared by using the spray spectra, spray deposition and spray sedimentation parameters. The result indicated that, the rotary cage atomizer generally gave droplet spectra with lower Dvo.1 , D vo.5 and Dvo.9 values than the Backpack motorized Mistblower and the five EMTF air-shear nozzles. The ProptecTM rotary cage atomizes gave very fine droplets spectra with higher deposition than the Backpack mistblower and the five EMTF air-shear nozzles. The spray spectra D0.1, Dv0.5 and D0.9 for EMTF nozzles at 0.5 l min -1 flow rate were 42.7 µm, 100.9 µm and 195.4 µm; and 46.7 µm, 107.0 µm and 206.1 µm for both N3 and N5 respectively. The deposition percentage for N3 (Lechler FT 5 – 608 + Lechler LU 120-015 POM) and N5 (Lechler FT 5 - 608 + Tee Jet XR8004 VK) were 57.7 % and 58.8 % at flow-rate 1.0 l min-1. The sediment percentage for N3 (Lechler FT 5 – 608 + Lechler LU 120-015 POM) and N5 (Lechler FT 5 - 608 + Tee Jet XR8004 VK) were 16.3 % and 14.6 % at flow-rate 0.5 l min-1.

Effects of adjuvants on deposition efficiency of fenhexamid sprays applied to Chardonnay grapevine foliage

Adequate spray deposition on susceptible grapevine tissue is an essential requirement for effective chemical control of economically important diseases, such as grey mould, powdery mildew and downy mildew. The objective of this study was to evaluate the potential of some agricultural adjuvants to improve foliar spray deposition. Deposition quantity and quality was assessed by means of a spray assessment protocol using fluorometry, photomicrography and digital image analyses. The visual droplet rating technique developed by G Furness, Australia, was also included in initial assessments. Both assessment protocols showed that spray deposition quantity increased with increasing spray volume applications of 27 l ha −1 to 581 l ha −1 with a motorised backpack mistblower, but decreased at 698 l ha −1, possibly due to run-off. Addition of selected spray adjuvants at 526 l ha −1 volume demonstrated improved deposition quantity and quality. Agral 90 (ethoxylated alkylphenol), BB5 (acidifier), Nu-film-P (terpene oil), and Solitaire (silicone/plant oil) significantly improved deposition on upper and lower leaf surfaces compared with the fenhexamid-only and water sprayed control. Break-thru S240 (organosilicone) and Villa 51 (alkylpolyethylene glycol ether) did not improve deposition quantity, although remarkably better deposition quality was obtained. An adjuvant concentration effect (within the registered concentration range) was evident at spray volumes of 502 l ha −1, especially those retained on the upper leaf surfaces. Agral 90 and Nu-film-P effected significant improvement of spray deposition at the higher concentrations (18 ml and 50 ml hl −1, respectively), but not at the lower concentrations (6 ml and 20 ml hl −1, respectively). Solitaire improved deposition at the lower concentration tested (50 ml hl −1), whereas reduced deposition at the higher concentration (100 ml per hl −1) was attributed to excessive spray run-off. No significant improvement of spray deposition was observed for both concentrations tested with Villa 51 (50 and 100 ml hl −1). Spray mixtures with adjuvants Agral 90 and Solitaire yielded similar deposition values at 500 l ha −1 compared with the fenhexamid-only control at 720 l ha −1, but reduced deposition at the higher spray volume, possibly due to spray run-off. This study clearly demonstrated the potential of adjuvants to improve deposition quantity and quality, but highlights the necessity to match adjuvant concentrations and application volumes on the spray target to achieve maximum spray deposition.

Phenology, Natural Enemies, and Efficacy of Horticultural Oil for Control of Chionaspis heterophyllae (Homoptera: Diaspididae) on Christmas Tree Plantations

Pine needle scale, Chionaspis pinifoliae (Fitch), and Chionaspis heterophyllae Cooley are important pests of Scots pine, Pinus sylvestris L., and other conifers in much of North America. On Christmas tree plantations, these insects are typically controlled by spraying broad-spectrum insecticides when the vulnerable immature stages are present. However, effective control of bivoltine populations can be difficult to achieve due to asynchronous hatch and development of the second generation. Our objectives were to 1) determine the phenology of the second generation of C. heterophyllae in Michigan; 2) characterize the natural enemy complex; and 3) assess the effectiveness of horticultural oil for control of C. heterophyllae on P. sylvestris Christmas tree plantations. We monitored scale populations in three counties in lower Michigan for 3 yr. Scale phenology was consistently associated with cumulative degree-days base 10 degrees C (DD(10 degrees C)). Second-generation egg hatch began at approximately 1230-1300 DD(10 degrees C), and continued for approximately 3 wk. The peak of the second instar coincided with 1500-1600 DD(10 degrees C). Common predators included the coccinellids Chilocorus stigma (Say) and Microweisia misella (LeConte). On average, 70% of the C. heterophyllae population in unsprayed fields was killed by predators in 1999. Two endoparasitic wasps, Encarsia bella Gahan and Marietta mexicana Howard (Hymenoptera: Aphelinidae), also were recovered. In 2000 and 2001, we applied a highly refined horticultural spray oil with a backpack mist blower at 1500-1600 DD(10 degrees). Scale mortality on trees treated with oil ranged from 66 to 80% and was similar to control achieved using conventional insecticides in both years.

Biological control of Oligonychus perseae (Acari: Tetranychidae) on avocado: IV. evaluating the efficacy of a modified mistblower to mechanically dispense Neoseiulus californicus (acari: phytoseiidae)

A Stihl SR400 backpack mistblower was modified to mechanically dispense the phytoseiid predator, Neoseiulus californicus (McGregor) onto artificial and actual avocado trees. The ability of the mistblower to broadcast N. californicus vertically was initially evaluated on a group of four artificial trees (4 m height). Distribution of corn grits, the carrier material in which N. californicus is commercially packaged, was unevenly distributed. Analysis of sticky cards arranged at 0.5 m intervals on artificial trees indicated that 75% of grits adhered to cards at heights ranging from 1.5-3.5 m. In an avocado orchard, the efficacy of three treatments for dispensing N. californicus was assessed: (1) mistblower application of phytoseiids mixed with corn grits with water setting on 0.5 (provided a fine spray to adhere predators and grits to leaves); (2) mistblower application of phytoseiids mixed with corn grits with water setting on 1.0 (provided a coarse spray); and (3) 4-point hand-release of predators into 10 paper cups placed evenly around trees at shoulder height. Each release strategy used about 19,000 predators and all treatments were compared to control trees that were not treated with N. californicus to determine naturally occurring densities of this predator on experimental trees. The mistblower successfully dispensed viable N. californicus mixed with com grits onto avocado trees. Predators on trees treated with the mistblower were recovered in the field up to 16 days post-application. However, 5-fold higher levels of N. californicus were recovered from hand-release applications. These tests on artificial trees and avocado trees demonstrated the potential of the mistblower for field applications of viable phytoseiids for control of spider mites on trees.

The Effects of a Fungal Biocontrol Agent and a Chemical Adjuvant on the Efficacy of Cuprous Oxide Sprays for Controlling Witches’ Broom Disease in Cocoa

A Field experiment was carried out in a cocoa plantation in Brazil to evaluate whether a fungal biocontrol agent (Trichoderma spp.) and a chemical adjuvant could enhance the efficacy of cuprous oxide sprays that are applied to control witches’ broom disease. The experimental design was comprised of 16 plots containing approximately 50 mature cocoa trees each. Each plot measured approximately 1000 m2. Treatments were allocated to plots randomly. Treatments were: control (no spray), cuprous oxide, cuprous oxide plus adjuvant, and cuprous oxide plus adjuvant plus fungus. Sprays were applied monthly from April to September in line with official recommendations for the control of witches’ broom disease. Sprays were applied using a motorized backpack mistblower. Monthly assessments of disease incidence were made from March to November. Assessments were made on five randomly selected trees from 15 marked trees located in the center of each plot. Assessments were comprised of the numbers of healthy and diseased pods observed on trees, the numbers of green and necrotic axillary and terminal brooms, and the numbers of healthy and diseased pods taken from trees at each harvest. The results show that disease incidence was the highest in the control plots where the fewest healthy pods were harvested. The overall incidence of disease varied from 25 to 45% across all treatments. Statistically, the results show that there were no significant differences among treatments, including the control. No significant improvements in the efficacy of copper-based sprays were measured as a result of adding the fungus or the adjuvant to the spray. Also, no significant improvements in disease control were recorded when using cuprous oxide on its own. We concluded that copper sprays were ineffective in controlling the disease. This paper discusses our results in the light of official recommendations for the control of the disease.

Evaluation of Acaricides for Control of Spider Mites on Almonds and Impact on Two Beneficial Arthropods, 1997

Abstract Twenty treatments were evaluated in an orchard near Modesto, CA, to determine their ability to control spider mites and to assess their impact on two beneficial arthropods. The experimental design was a RCB with 4 replications. Trees were in the ground for three years and were approximately 7 ft in diameter and 10 ft tall. Sprays were applied with a 5-hp backpack mist blower on 8 July in 100 gallons of water per acre. Although this was a concentrate application, coverage was excellent due to the small size of the trees and the directed application. Prior to the research application, the grower had applied a field rate of Ambush for worm control with a commercial speed sprayer. Spider mites were monitored by removing 50 leaves per tree, brushing onto glass plates and counting pests and beneficials with a binocular dissecting microscope at 15X.

Evaluation of Acaricides for Control of Spider Mites on Watermelon, 1997

Abstract Six treatments were evaluated in a field near Farmington, CA to determine their efficacy in controlling spider mites. The experimental design was a RCB with 4 replications. Sprays were applied with a 5-hp backpack mist blower on 31 July in a volume of 100 gpa. One lb of Orthene SP/acre was applied as a maintenance spray due to aphid pressure. Infestations were monitored by removing 10 leaves per plot and counting with a binocular dissecting scope at 15X.

Evaluation of Acaricides for Control of Spider Mites on Watermelons, 1996

Abstract Five treatments were evaluated in a commercial field near French Camp, CA, to determine their efficacy in controlling spider mites. The experimental design was a RCB with 4 replications. Sprays were applied with a backpack mist blower on 28 Jun and 11 Jul in 80 gpa. Infestations were monitored by removing 10 leaves per plot and counting the number of aphids and mites. For the mites, leaves were passed through a mite-brushing machine and then counting mites under a binocular dis-secting scope at 15X.

Red Imported Fire Ant Control in Bahiagrass Pastures, 1996

Abstract Test 1, located in Atmore, AL, was a RCB design with two replications, each block being in two adjacent, closely grazed bahiagrass paddocks on sandy, Coastal Plain soil. Plot size was 5-8 acres per plot, dictated by the irregular shape of the paddocks. The insecticide Amdro was applied in late afternoon on 16 May 1995 with a Solo brand backpack mistblower, in 20 ft wide swaths (within-swath rate of 3 lb bait/acre), alternating with 20 ft untreated swaths. Treatments were evaluated 16 May, 14 Jun, and 12 Oct 1995, and 7 Aug 1996, by counting number of active fire ant mounds in one, 60 ft by 200 ft transect, randomly located in each plot. The same transect was used on each evaluation in 1995. A new transect was located in each plot in 1996. The transect ran across swaths in the treated plots. A thin rod was inserted with minimal disturbance into each mound, to determine colony activity. Test 2, located in Brewton, AL, was a CRB design with two replications in a bahiagrass pasture. The paddocks were on sandy, Coastal Plain soil. Plot size ranged from 1.5-2.5 acres per plot, dictated by the irregular shape of the pasture. The insecticide was applied in afternoon on 30 Apr 1996 with a Herd GT77-A spreader, at a within swath rate of 1.5 lb bait/acre. Insecticide was applied in alternating 30 ft wide swaths, or as a conventional broadcast treatment. Treatments were evaluated 24 May and 7 Aug 1996, using same methods as in Test 1.

Spring Management of Cooley Spruce Gall Adelgid with Highly Refined Horticultural Spray Oil, Insecticidal Soap, Tempo, and Sevin on Douglas-Fir in Lehighton, Pennsylvania, 1994

Abstract Seven treatments were applied to evaluate Cooley spruce gall adelgid on heavily infested 6-8 ft Douglas-fir Christmas trees. Treatments were applied on 14 Apr, arranged in a RCB design, replicated 4 times. Foliar treatments were completed by using a Solo Master 412 back pack mist blower operating at full throttle on setting two. Treatments were applied at the rate of 150 gal/A (454 ml/tree). At treatment time the following conditions existed: air temperature, 69°F; 45%RH; water pH, 6-7; and skies were clear. Posttreatment counts were completed on 30 DAT. Each treatment was evaluated by selecting four cardinal locations on each tree at breast height, and counting the total number of life stages (nymphs, adult females with egg masses) over a 15 sec count on 1994 needle growth at each location. Each tree was rated on 1 Aug (109 DAT) to determine effect of treatments on needle quality. Each treatment was evaluated by selecting four cardinal locations on each tree at breast height, and counting the total number of Cooley spruce gall adelgid damaged 1994 needles over a 15 sec count.

Forest Ant (Hymenoptera: Formicidae) Effect on Gypsy Moth (Lepidoptera: Lymantriidae) Larval Numbers in a Mature Forest

In a previous study, ants had a significant effect on gypsy moth, Lymantria dispar (L.), numbers in a forest where the trees were only about 3 m high. The present study was carried out similarly, but trees were about 20 m high. In some plots, ant numbers were suppressed by a combination of barriers and poison baits. In other plots, 24% sucrose sprays were applied with a back-pack mist blower in an attempt to increase ant abundance, but no increases occurred. There was a nonsignificant trend for caterpillar numbers to be higher in the plots where ants were suppressed, and gypsy moth larval counts on leaves of trees were negatively correlated with ant counts on leaves. Thus, there is evidence that ants have an effect on gypsy moth caterpillars in mature forests as well as in young ones.

Management of Cooley Spruce Gall Adelgid at Bud Break with Insecticidal Soap, Highly Refined Horticultural Spray Oil, and Carbaryl on Douglas-Fir in Lehighton, Pa, 1993

Abstract Three treatments were applied to evaluate control of Cooley spruce gall adelgid on heavily infested 6-8 ft Douglas-fir Christmas trees. Treatments were applied on 10 May and arranged in a randomized complete block design. Each treatment was replicated four times. Foliar treatments were completed by using a Solo Master 412 back pack mist blower operating at full throttle on setting two. Treatments were applied at the rate of 150 gal/acre (454 ml/tree). At treatment time the following conditions existed: air temperature, 84°F; water pH, 7.0; 65% RH, and skies were clear. Posttreatment counts were completed on 21 May. Each treatment was evaluated by selecting four cardinal locations on each tree at breast height, counting 25 needles (1993 growth) at each location, and recording those needles infested with mature female adelgids and egg masses. Each tree was rated to determine the effect of treatment on tree quality on 14 Jul.

Spring Management of Cooley Spruce Gall Adelgid with Highly Refined Horticultural Spray Oil and Conventional Insecticides on Douglas-Fir in Lehighton, Pa, 1993

Abstract Seven treatments were applied to evaluate Coole&amp;gt; spruce gall adelgid on heavily infested 6-8 ft Douglas-fir Christmas trees. Treatments were applied on 20 Apr and arranged in a randomized complete block design. Each treatment was replicated four times. Foliar treatments were completed by using a Solo Master 412 back pack mist blower operating at full throttle on setting two. Treatments were applied at the rate of 150 gal/acre (454 ml/tree). At treatment time the following conditions existed: aii temperature, 71°F; 60% RH; water pH, 7.0; and skies were clear. Posttreatment counts were completed on 21 May. Each treatment was evaluated b&amp;gt; selecting four cardinal locations on each tree at breast height, and counting the total number of stem mothers with eggs masses over a 15 s count on both 1991 and 1992 needle growth at each location. Each tree was rated on 14 Jul to determine the effect of treatments on tree quality.

Spring Management of Cooley Spruce Gall Adelgid with Soap, Oil, Experimental and Conventional Insecticides on Douglas-Fir, in Lehighton, Pa, 1992

Abstract Twelve treatments were applied to evaluate Cooley spruce gall adelgid on heavily infested 6-8 ft Douglas-fir Christmas trees. Treatments were applied on 23 Apr, arranged in a randomized complete block design, replicated four times. Foliar treatments were applied using a Solo Master 412 back pack mist blower operating at full throttle on setting two, at the rate of 150 gal/acre (454 ml/tree). At treatment air temperature was 78°F; 45% RH; and skies were clear. Posttreatment counts were completed on 3 Aug. Each treatment was evaluated by selecting four cardinal locations on each tree at breast height, and counting 50 needles at each location and recording the number of Cooley spruce gall damaged needles. A total of 200 needles was examined per tree and converted to % damaged needles.

Flowering Crab, Control of Fall Webworm, Wooster, Ohio, 1990

Abstract Flowering crabapple trees, 2-4 m tall, growing in a research plot at the OSU/OARDC campus, were used to evaluate efficacy of selected insecticides against fall webworm larvae. Twigs having small tents were removed, 4 Sep, from Mortis in Allen Co., OH, placed in plastic bags and transported to Wooster in coolers. Tents were attached to Malus trees with a Twistee at the OARDC research plot. A KWH backpack mistblower, operating at half-throttle on aperature setting # 3 for 30 sec, was used to deliver about 600 ml of finished spray to each tree. Sprays were directed toward the web and surrounding foliage on each of 3, single-tree replicates per treatment. Sprays were applied 8 Sep when conditions were cloudy, 21°C, with 0-8 km/h winds. There were 2.5 cm of rainfall in the experimental area during the test period. Treatment effectiveness was evaluated 5 DAT by dismantling each web and assessing larval condition.