Aphid Counts Research Articles

Variation for Resistance to Aphids (Homoptera: Aphididae) Among Tomato Inbred Backcross Lines Derived from Wild <I>Lycopersicon</I> Species

Two tomato inbred backcross line (IBL) populations, derived from crosses between aphid-susceptible Lycopersicon esculentum Mill. 'Peto 95-43' X resistant wild L. pennellii Corr (D'arcy) accession LA716, and Peto 95-43 X resistant wild L. hirsutum f. glabratum Mull accession LA407, were evaluated in replicated field experiments for resistance to potato aphid, Macrosiphum euphorbiae (Thomas), and green peach aphid, Myzus persicae (Sulzer). Aphid infestation scores for each IBL and control (LA716, LA407, Peto 95-43, and susceptible 'Alta') plot were recorded weekly for 5 and 9 wk during the summers of 2000 and 2001, respectively. Aphid infestation scores from leaflets were used to calculate area under the infestation pressure curve (AUIPC), a measure of aphid infestation throughout the growing season, for each IBL and control. Score AUIPC was highly correlated with actual aphid count AUIPC, indicating that scores accurately reflected aphid infestation. Score AUIPC was also highly correlated across both years (2000 and 2001) and locations. Low score AUIPC was significantly correlated with larger plant size and sprawling, indeterminate plant growth habit. Seven IBLs, LA716, and LA407 were significantly more resistant to aphids (lower score AUIPC) than susceptible parent Peto 95-43 in both years. Two IBLs, 1034 and 1051, were not significantly different from resistant LA407 for score AUIPC in both years. The seven aphid-resistant IBLs identified here can be useful as donor parent material for resistance breeding efforts in cultivated tomato.

ORGANIC TOMATO PRODUCTION IN OKLAHOMA

Plots were established at the Lane Agricultural Center in Lane, Okla., in 2003 for the purpose of conducting research in certified organic vegetable production. A field was selected that had been in pine timber since 1985. The field was cleared, plowed, disked, and land-planed. To establish a baseline for future reference, soil samples were collected on a 30 × 30 ft grid. Lime was added to adjust the pH. Poultry litter was added to the field as a fertilizer, and was incorporated by disking. Turnips were grown as a cover crop during the winter of 2003–04. In Spring 2004, the field was divided into four equal sections, which were planted with either tomatoes, sweet corn, watermelons, or southern peas. Tomatoes were planted using both determinate and indeterminate types. Plants were selected based on reported properties of interest to organic growers, such as disease resistance, pest resistance, or heat-set capabilities. The cultivars with greatest yield were Sunny, Solar Set, Classica, Sun Leaper, and Mountain Fresh. Visual disease ratings were taken throughout the season. Copper sulfate was used as a fungicide. The cultivars with the lowest disease ratings were Amelia, Peron, Celebrity, Florida 91, and Mountain Fresh. The major insect pest throughout the season was aphids. Aphid counts reached 6.9 aphids per leaf on 11 June. Two applications of AzaDirect, a neem extract, reduced aphid populations to 1.0 aphid per leaf on 17 June, 0.1 aphid per leaf on 25 June, and 0 aphids on 9 July.

Within-Plant Distribution ofAcyrthosiphon kondoi(Homoptera: Aphididae) on Alfalfa

Abstract The goal of this research was to describe within-plant distribution for Acyrthosiphon kondoi Shinji and Kondo on alfalfa (Medicago sativa L.). Alfalfa entries used in this study were from breeding lines selected for moderate and high levels of resistance to A. kondoi and from the susceptible cultivar ‘OK08’. From each of the three entries, three stems on each of 12 established alfalfa plants grown in pots were infested with aphids when stems had four to five nodes. At 2-d intervals through 10 d after infestation, stem heights, numbers of nodes per stem, and numbers of trifoliolates per node (as axillary branching occurred) were recorded. Also recorded for each node were numbers of A. kondoi on leaf blades, petioles, and the internodal stem section below the node. Aphid counts were analyzed to determine significant differences among alfalfa entries and among plant parts (leaf blades, petioles, and stem sections) within entries. Plant profiles were prepared to show within-plant distributions. Regre...

Analysis of spatial patterns at a geographical scale over north-western Europe from point-referenced aphid count data

The spatial analysis by distance indices (SADIE) technique was developed to evaluate the spatial pattern of point-referenced count data as well as the spatial association between two sets of data sharing the same point locations. This paper presents an analysis of spatial patterns in aphid count data and the association of these data with climate across north-west Europe. The paper tests the applicability of the technique to large geographical areas. Aggregation and cluster indices were calculated for the total annual abundance of the peach-potato aphid Myzus persicae (Sulzer) and for the annual mean rainfall and temperature at aphid monitoring sites. Association indices demonstrated the stability in time of aphid spatial structures and the correlation between aphid density and climate patterns. Groups of relatively large numbers of aphids, termed patches, and groups of relatively small numbers of aphids, termed gaps, were located and their mean size estimated. The aphid patterns were quite stable in time and the spatial patterns of temperature and rainfall were weakly associated with M. persicae annual abundance. Similarities were observed between the results of SADIE and those from the more widely used technique of spatial autocorrelation (SAC). However, the SADIE association index has the advantage of quantifying the possible associations between aphid data and the factors that determine population distribution. Thus, high temperature and low rainfall were identified as environmental factors that were positively associated with aphid abundance across north-west Europe.

Effects of mowing frequency on densities of natural enemies in three Pacific Northwest pear orchards

AbstractEffects of mowing frequency on ground cover composition and on numbers of predators, parasitoids, and select phytophagous arthropods in the ground cover of three reduced‐insecticide pear orchards were determined. Concurrent samples taken in the tree canopy (with beating trays) and in the herbicide strips on the orchard floor (with pitfall traps) tested whether counts of natural enemies in these two habitats were also affected by mowing regime. A reduction in frequency of mowing from two to three times per month (= control) to once per month or once per growing season led to increased cover of grasses, broadleaf plants, and broadleaf plants in flower. Sweep net samples of natural enemies in the ground cover were dominated numerically by spiders (Araneae), parasitic Hymenoptera, and predatory Heteroptera, with lesser numbers of other taxa (Syrphidae, Neuroptera, Coccinellidae). Predators and parasitoids showed substantial increases in numbers associated with decreased mowing frequency. Sweep net counts of aphids, Lygus spp. (Heteroptera: Miridae), and leafhoppers/planthoppers, all potential prey of predators, also increased significantly with decreased mowing frequency. In the pitfall samples, only the European earwig (Forficula auricularia L.) (Dermaptera: Forficulidae) exhibited a change in counts associated with mowing treatment; numbers of earwigs in pitfall traps declined as mowing frequency decreased. For the beat tray samples, mean tray counts for most natural enemy taxa were higher in the less frequently mowed plots, but significantly (P < 0.05) so only for two taxa: spiders and a predatory mirid, Deraeocoris brevis (Uhler) (Heteroptera: Miridae). It remains to be determined whether biological control of pests in the tree canopy can be enhanced by manipulating mowing frequency. Questions raised by this study include whether there is extensive movement by natural enemies between the ground cover and tree canopy, and whether plot size affects the likelihood of showing that mowing frequency influences predator densities in the tree canopy.

Effects of plant spacing and interplanting with oilseed rape on colonisation of dwarf hops by the damson‐hop aphid, Phorodon humuli

AbstractThe pattern of colonisation of dwarf hops (Humulus lupulus) by damson‐hop aphid (Phorodon humuli (Schrank)) migrating from Prunus spp. was investigated at six plant spacings and where some of the hops were replaced by oilseed rape (Brassica napus L.), a non‐host of the aphid. The number of migrant aphids that accumulated on hop stems (bines) increased with increasing bine size and density. The numbers of aphids that colonised hops interplanted with oilseed rape reflected the density of the hop plants only and not the overall plant density. As the physical size of the wind shadow within which flying aphids can manoeuvre and land was unimportant unless provided by a host plant, the finding supports the theory that flying aphids respond to olfactory stimuli associated with their hosts. Variation in bine height (as a measure of plant size) explained 29–93% of the variance in aphid counts during the 3 years' study and bine density 1–14%. Standardising the data as the numbers of aphids per metre of bine and taking a square‐root transformation of these standardised counts improved the precision of the analyses and, by stabilising variances, facilitated comparisons between years as growth became more vigorous as the plants matured. Each year, the rate of increase in numbers of aphids settling on plots of hops declined curvilinearly with increasing bine density. Maximum colonisation by P. humuli occurred at a bine density of five per metre row, a density similar to that used commercially by growers of dwarf hops.

Variation for aphid resistance and insecticidal acyl sugar expression among and within Lycopersicon pennellii‐derived inbred backcross lines of tomato and their F1 progeny

AbstractFive inbred backcross lines (IBL) were selected for higher relative expression of insecticidal acyl sugars (rank average) from an inbred backcross population derived from the cross Lycopersicon esculentum cultivar ‘Peto 84’×Lycopersicon pennellii accession LA716. These five BC2S5 IBLs were crossed in a partial diallel design (Method II), and their self and F1 progeny and three control cultivars were tested at two California field locations in 1996. Counts of potato aphids, Macrosiphum euphorbiae Thomas, on leaves, as a measure of plant infestation, revealed significant general combining ability (GCA) for lower aphid numbers with IBL44 and IBL59; the F1 hybrid IBL44 × IBL59 had significantly fewer aphids per leaflet than the susceptible cultivar ‘Alta’. GCA for acyl sugars was associated with IBL59 only. Of all the IBL and IBL × IBL F1 hybrids, only IBL59 produced significant levels of acyl sugars. Significant within IBL59 variation for acyl sugars was observed, but not for aphid resistance. Our results suggest that factors other than acyl sugars contributed to L. pennellii‐derived aphid resistance in IBL × IBL F1 hybrids and IBL that do not produce significant amounts of acyl sugars. IBL59 and IBL44 may be useful for breeding for aphid resistance in cultivated tomato.

Simulation of counts of aphids over two hectares of Brussels sprout plants

Abstract Populations of the mealy cabbage aphid, Brevicoryne brassicae (L.), on Brussels sprout plants, Brassica oleracea (L.) were sampled, fortnightly throughout the early season of 1996, in 2 ha 2 blocks. Sampling was done on two spatial scales, firstly over 25, 5×5 m sample areas, and then on the 20 plants within each of these areas. On each occasion, the occurrence of aphids was recorded on all the 500 plants sampled per block (one in 16 plants) and the count of the number of aphids per plant measured on a selected five plants per area, yielding information from 125 plants per block (one in 64 plants). The data were analysed to study various aspects of the aphids’ frequency distribution at each of the two scales, particularly the relationship between variability and population density, and the relationship between the proportion of plants infested and density. Patterns of the incidence of infestation differed radically between the two blocks. Also, for a given aphid density, more plants were infested as the season progressed, and at that density there were therefore, on average, fewer aphids per plant at later dates. Methodology was outlined to simulate realistic aphid counts, conforming to the relationships found for each of the two scales around the time of the achievement of a threshold incidence of 10% infestation. This was used to generate a count for each of the 8000 plants per block, for each of the blocks, representing a 64-fold increase in information. It was verified that these simulations provided realistic sets of counts, that could be used subsequently to study the efficiency of aphid sampling schemes and to replace costly extensive surveys for the development of control strategies.

Analyzing maps of dispersal around a single focus

The spatial pattern of organisms may be used to characterize their dispersal, quantify spread or estimate the point of introduction of an alien species. Their distribution may be represented by maps of individuals, or by counts or by presence/absence at known positions within a sampled area. The problems and relative merits of these different forms of data for spatial inference are discussed. Three datasets concerning dispersal from a single focus are analyzed: counts of aphids, Rhopalosiphum padi and Sitobion avenae, on barley plants, Hordeum vulgare, grown in experi- mental trays; mapped locations of couch grass, Elymus repens, tillers within plots of a field experiment; locations of sightings of the lupin aphid, Macrosiphum albifrons, as it invaded Great Britain between 1981 and 1984. A method for generating maps from counts is proposed to overcome problems caused by recording imprecision. Several statistics are used to quantify dispersal and spatial pattern in the experimental data and together provide a clear picture of the spatial pattern observed; they enabled several effects of the experimental treatments to be identified. The value of the statistics are compared. Estimates of the source of the lupin aphid invasion are obtained using the backtracking methods of Perry (1995b) and do not contradict previous suggestions.

Green Peach Aphid Control with Foliar Sprays, 1997

Abstract Experimental plots were established on the UI Research and Extension Center, Kimberly, Idaho. Potatoes were planted on 28 Apr and irrigated by solid set sprinkler. The soil type was Portneuf silt loam. Seven treatments and one untreated check plot were replicated four times in a randomized complete block design. Individual treatment plots were 4 rows (36-inch row spacing) wide by 25 ft long with 5-ft alleyways separating the plots. Green peach aphids were mass reared on greenhouse mustard plants (Brassica juncea L. ‘Florida Broadleaf’) for release into individual plots. Aphid releases were made into test plots on 14 Jun. A total of four heavily infested leaves were used to inoculate each plot. Treatment sprays were broadcast applied using a CO2-pressurized backpack sprayer (30 psi) and delivering 20 gal finished S per acre (four, 10X hollow-cone nozzles). Aphid counts were made by non-destructively sampling leaves at random from the top, middle, and bottom sections of plants in the center two rows of each plot. The data collected and presented is the total no. of aphids per 20 leaves. On 25 Jun a pre-treatment count was made and all treatments were applied later that d. Data was analyzed using ANOVA and Newman-Keuls multiple means comparison (Significance Level P = 0.05).

Control of Aphids on Irish Potato, 1996

Abstract The experiment was an RCB design replicated 5 times and was conducted at Presque Isle, ME on land that was in clover in 1995. It was planted 28 May. The 3.0-m space between blocks and the 1.8-m space between the four-row plots were sown to oats on 19 Jun. All rows were planted with an assisted-feed planter 0.9 m apart and 15.0 m long and the healthy whole Katahdin seed (approx. 75 g) were 30 cm apart. Fertilizer and hilling practices were normal for the area. Early and late blight were controlled by 7 foliar applications of mancozeb. Fur-row applications of insecticides were made by sprinkle can. Foliar insecticide applications were made with a Century boom sprayer, 3 nozzles per row at 5.6 kg/cm2 (80 psi) pressure and 0.47 kl/ha (50 gpa). Numbers of aphids (by species) were counted on a top, a middle, and a bottom leaf on 20 plants in the middle rows of each plot. When dates of count and application were the same, aphid counts were made prior to applications of the insecticide. Analy-ses of variance were calculated following transformation of the data using log10(x +1). Transformed means of the total number of wingless aphids were compared using Fisher’s LSD Test and then applied to the actual means. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was respectively 8.5, 11.8, and 6.2 cm. The average temperature for each of the same 3 months was 18.3, 19.4, and 20.0 deg. C.

Aphid Management on Head Cabbage, 1997

Abstract The study was conducted at the substation of the Kula Research Station, Maui Agricultural Park. A RCB design with six treatments and four replications (blocks) was used. Each treatment plot consisted of a single row of cabbage planted [ at 18-inch between-plant spacing. Each row consisted of 45 plants for a total length of approximately 70 ft. Treatment plots were separated by a 48-inch ; spacing. Blocks were separated by a 60-inch spacing. Total field size was 0.15 acre. Admire was applied on 25 Jun, one week after transplanting seedlings i into the field. A hand injector was used to place the insecticide in the root zone. The field was irrigated immediately following the Admire application. Foliar treatments were applied on 22 Jul at a rate of 100 gpa and 60 psi using a CO2 backpack sprayer. The spray wand was equipped with a single hollowcone TX-26 nozzle. Aphid counts were made at pre-treatment, 6, 13, and 20 DAT. In conducting the surveys, the same ten plants in each treatment plot were examined. Alatae and apterous counts were made for the pre-treatment, 6 and 13 DAT surveys. Only the total number of aphids was recorded in the I last survey. Aphid species were identified by the Entomology Department’s insect taxonomist.

Control of Aphids on Irish Potato, 1997

Abstract The experiments were RCB designs replicated 5 times and were conducted at Presque Isle, ME on land that was in clover in 1996. They were planted 02 Jun. The 3.0-m space between blocks and the 1.8-m space between the four-row plots were sown to oats on 10 Jun. All rows were hand planted 0.9 m apart and 15.0 m long and the healthy whole Katahdin seed (ca. 75 g) were 30 cm apart. Fertilizer and hilling practices were normal for the area. Early and late blight were controlled by 7 foliar applications of mancozeb. Furrows applications of insecticides were made by sprinkle can. Foliar insecticide applications were made with a Century boom sprayer, 3 nozzles per row at 5.6 kg/cm2 (80 psi) pressure and 0.47 kl/ha (50 gpa). Numbers of aphids (by species) were counted on a top, a middle, and a bottom leaf on 20 plants in the middle rows of each plot. When dates of count and application were the same, aphid counts were made prior to applications of the insecticide. Analyses of variance were calculated following transformation of the data using log10(x + 1). Transformed means of the total number of wingless aphids were compared using Fisher’s LSD Test and then applied to the actual means. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was respectively 5.6, 6.6, and 10.3 cm. The average temperature for each of the same 3 months was 17.7, 20.8, and 18.3 deg. C.

Insecticide Evaluation I, 1997

Abstract This experiment was conducted in 3 miniblocks, each ⅓ acre, of 19-yr-old trees on MM.lll rootstock. Trees measured 15 ft in height and 14 ft in width and were planted at a spacing of 20 X 20 ft. The experimental design consisted of 6 single-tree replica tions per treatment, with 2 replications per mini-block in a randomized block design. Each replicate was surrounded by 1 unsprayed tree on each side. Insecticides were applied as complete sprays to both sides of the trees with a Swanson DA5OOA airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 100 gpa. Dates of application were 4 Apr [delayed dormant (DD)], 10 Apr [pink (P)], 12 May [petal fall (PF)], 21 May [10-20 mm fruit diameter], 27 May [first cover (lC)], 11 Jun [second cover (2c)], 24 Jun [third cover (3C)], 8 Jul [fourth cover (4C)], 22 Jul [fifth cover (5C)], 5 Aug [sixth cover (6C)], 19 Aug [seventh cover (7C)], and 2 Sep [eighth cover (8C)I. Other materials applied separately to all treatments were Agri-Mycin, COCS, Dithane, Nova, Penncozeb, Topsin-M, and Ziram. Treatment effect was determined by counting arthropods on test trees periodically during the season. RAA control was determined by counting colonies per tree. Control of WALH was determined by counting nymphs on the underside of 25 leaves per tree. Effect of treatments on STLM was determined by counting all tissue-feeder mines during a 5 minute period per tree. Control of SA was evaluated by counting aphids on the most infested leaf on each of 10 terminals per tree. Effect of treatments on MAL was determined by counting adults and larvae on 10 terminals per tree. Treatment effect against ERM and ARM was determined by sampling 25 leaves per tree (4 replications), removing mites with a mitebrushing machine, and counting motile stages with a binocular microscope. Control of fruit-feeding insects was determined by scoring for injury 100 picked apples and up to 100 drop apples per replication on 23 Sep.

Insecticide Evaluation II, 1997

Abstract This experiment was conducted in a 0.8 acre block of 17-yr-old trees on MM106 rootstock. Trees measured 13.5 ft in height and 14.5 ft in width and were planted at a spacing of 18 X 24 ft. The experimental design consisted of a single plot of 3 rows X 8 trees/row for each of two spray treatments which were separated by a single untreated plot of 4 rows X 8 trees/row. Insecticides were applied as complete sprays to both sides of the trees with a Swanson DA500A airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 100 gpa in treatment 1 and 250 gpa in treatment 2. Dates of application were 2 May [petal fall (PF)], 14 May [first cover (1C)], 29 May [second cover (2C)], 12 Jun [third cover (3C)], 24 Jun [fourth cover (4C)], 8 Jul [fifth cover (5C)], 22 Jul [sixth cover (6C)], 5 Aug [seventh cover (7C)], 19 Aug [eighth cover (8C)], and 2 Sep [ninth cover (9C)]. Other materials applied separately to all treatments prebloom were COCS, Dithane, and Nova. Other materials applied postbloom at various times in tank mix with treatment 1 were Nova, Dithane, Topsin-M, and Ziram. Treatment effect was determined by counting arthropod pests or injury on 4 single-tree replications of ‘Delicious’ for European red mite, and ‘Golden Delicious’ for all other pests, in each plot periodically during the season. RAA control was evaluated by counting colonies per tree. Control of SA was determined by counting aphids on the most infested leaf on each of 5 terminals per tree. Treatment effect against WALH and RLH was determined by counting nymphs on the underside of 25 leaves per tree. PLH control was determined by counting adults and nymphs on the 5 youngest leaves on each of 10 terminals per tree. Effect of treatments against ERM was deter-mined by sampling 25 leaves/tree, removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope. STLM control was evaluated by counting all tissue-feeder mines during a 5 minute period per tree. Control of fruit-feeding insects was determined by scoring for injury 100 picked apples and up to 100 drop apples per replication of ‘Golden Delicious’ on 17 Sep. ‘Golden Delicious’ fruit were also rated for russeting as 0 (no russet), 1 (raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or 5 (>50% russeted surface).

Novartis Products Evaluation, 1997

Abstract This experiment was conducted in a 2.4-acre block of 3-yr-old trees on EMLA, 26 rootstock (‘Rome’ and ‘Golden Delicious’) and Mark rootstock (‘York’). Trees measured 8 ft in height and 6.5 ft in width and were planted at a spacing of 12X18 ft. The experimental design consisted of a single plot of 12 rows (4 of each variety) X 10 trees/row for each of three spray treatments and an untreated plot. Insecticides were applied as complete sprays to both sides of the trees with a FMC Economist airblast sprayer, which traveled at 2.2 mph and delivered a spray volume of 200 gpa for the delayed dormant (½-inch green) application and 75 gpa for all other applications. Dates of application were 3 Apr [delayed dormant (DD)], 11 Apr [pink (P)], 16 May [petal fall (PF)], 28 May [first cover (IC)], 12 Jun [second cover (2C)], 24 Jun [third cover (3C)], 10 Jul [fourth cover (4C)], 25 Jul [fifth cover (5C)], 11 Aug [sixth cover (6C)], and 25 Aug [seventh cover (7C)]. Other materials applied in combination were Captan (treatments 1-3), Dithane (treatments 1-3), Nova (treatment 3), Vangard (treatments 1 and 2), and Ziram (treatments 1-3). Treatment effect was determined by counting arthropod pests and injury on 4 single-tree replications of ‘Rome’ and ‘York’ periodically during the season. Control of WALH was determined by counting nymphs on the underside of 25 leaves per tree. Control of SA was evaluated by counting aphids on the most infested leaf on each of 5 terminals per tree. Effect of treatments against ERM was determined by sampling 25 leaves per tree (York only), removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope. Control of STLM was determined by counting all tissue-feeder mines during a 5-min period per tree. Control of fruit-feeding insects was determined by scoring for injury 100 picked apples per replication of ‘Golden Delicious’ on 17 Sep, and ‘Rome’ and ‘York’ on 25 Sep. ‘Golden Delicious’ fruit were also rated for russeting as 0 (no russet), 1 (raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or (5>50% russeted surface).

Colorado Potato Beetle and Green Peach Aphid Control with Soil-Applied Insecticides and Foliar Sprays, 1997

Abstract Experimental plots were established on the UI Research and Extension Center, Kimberly, Idaho. Potatoes were planted on 28 Apr and irrigated by solid set sprinkler. The soil type was Portneuf silt loam. Ten treatments and one untreated check plot were replicated four times in a RCB design. Individual plots were 4 rows (36-inch row spacing) wide by 25 ft long with 5-ft alleyways separating the plots. Green peach aphids were mass reared in the greenhouse on mustard plants (Brassica juncea L. ‘Florida Broadleaf’) for release into individual plots. Aphid releases were made into test plots on 14 Jun. A total of four heavily infested leaves were released per plot. On a weekly basis, adults, large larvae (3-4 instar), small larvae (1-2 instar), and egg masses of Colorado potato beetle were counted and percent defoliation estimates were made from whole plant inspections of the center 5 hills of the middle 2 plot rows. Green peach aphid counts were made by non-destructively sampling 20 leaves at random from the top, middle, and bottom sections of plants in the center two rows of each plot. The data collected and presented is the total no. of aphids/20 leaves. Admire treatments were applied at planting as an in-furrow S over the seed piece on 28 Apr. Temik and Thimet were applied in-furrow with the seed piece at-planting. Post-emergence Admire was side dressed and shanked on 29 May. Furadan and the at-emergence, pre-hilling Admire treatment were applied on 6 Jun. Furadan was applied in a six-inch banded S over the plants at 4-inch rosette stage of plant growth using a CO2-pressurized backpack sprayer. The at-emergence, pre-hilling Admire treatment was shanked to the side of the plants (3 inch to side and 4 inch deep) and then hilled. On 26 Jun the CGA-215944 and Sevin treatments were S applied. All foliar S treatments were broadcast applied using the backpack CO2 sprayer at a rate of 20 gpa (30 psi, with 4, 10X hollow-cone nozzles). On 28 Jul a second foliar application of Furadan was made. Data were analyzed using ANOVA and Tukey’s HSD Test.

Insect Control on Flue-Cured Tobacco with Systemic Insecticides, 1996

Abstract This experiment was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA to evaluate TA and TFB control on fluecured tobacco with various systemic insecticides applied as soil or transplant water treatments and to determine the impact of these treatments on tobacco yield. Twelve treatments and an untreated check were established in a RCB design with 4 replications. Plots, 4 X 40 ft (1 row X 24 plants), were separated by single guard rows. Pre-transplant soil treatments of all liquid formulations except Furadan were broadcast with a CO2-pressurized tractor sprayer that delivered 32 gpa at 30 psi through 8003 LP tips on 3 May (Ambient temperature 74-76 °F, soil temperature, 70 °F; soil pH, 5.7; OM, <2%). Treatments were immediately incorporated by double disking. Band applications of Furadan and Temik were made during bed formation and immediately covered with 6 to 8 inch of soil on 8 May. Furadan 4°F band treatments were applied in a 12-inch band using a COz-pressurized backpack sprayer that delivered 16 gpa through an 8003 E tip at 30 psi. Temik was applied in a 14-inch band using a tractor mounted-Gandy granular applicator. The soil was in excellent condition for both the pre-transplant soil and bedding treatments. ‘Coker 371Gold’ fluecured tobacco was transplanted into experimental plots in a Chesterfield-Mayodan-Bourne sandy loam soil on 20 May. A measuring cup was used to apply transplant water (TPW) treatments of Orthene and Admire in 4 fl oz/plant (204 gpa) at the base of each plant in the treatment plots. Except for insect control, production practices followed Virginia Cooperative Extension recommendations. Dipel (Bacillus thuringiensis) was applied for tobacco budworm and tobacco hornworm control on 26 Jun and 8 Aug. The foliar application of Orthene were applied on 5 Jul and Aug with a CO2-pressurized backpack sprayer that delivered 28 gpa through 3 TX-12 tips at 60 psi. TA populations were estimated on the upper 4 leaves of 10 plants/plot about once a week from 5 to 9 wk after transplanting. On 25 Aug, TA damage was rated on a scale of 0 to 10: 0 = no signs of aphid damage; 10 = very severe necrosis of leaves and extensive sooty mold. TFB feeding holes were counted on 5 plants/plot at 2 and 5 wk after transplanting. Tobacco was harvested and cured and yield was determined. Data were analyzed by ANOVA and significantly different means were separated. Aphid count data were transformed to log)0 (x + 1) before analysis. Actual means are presented in the table. Admire TOW gave the best seasonlong control of TA. The Temik and Temik + Mocap GEL treatment

Evaluation of Fulfill for Control of Cotton Aphids, 1996

Abstract Cotton was planted 20 Jun in 40-inch rows (8-row X 75-ft plots) at the Texas Agricultural Experiment Station at Chillicothe. The experimental design was a randomized complete block, with 5 insecticide treat-ments and a check replicated 4 times. Cotton was inspected for aphids on 2, 9, and 15 Aug. Ten leaves from the top half and 10 leaves from the lower half of plants from each plot were examined, and the numbers of aphids were recorded on each inspection date. Pre-treatment counts were made and the insecticide treatments were applied on 19 Aug. Treatments were applied with a John Deere High Cycle 6000 sprayer. Spray drops were used to provide three nozzles per row, delivering 9.7 gpa at 40 psi. Post-treatment aphid counts were made at 4, 6, and 13 DAT.

Evaluation of Combinations of Fulfill and Curacron for Control of Cotton Aphids, 1997

Abstract Cotton was planted 19 Jun in 40-inch rows (8-row X 75-ft plot) at the Texas Agricultural Experiment Station at Chillicothe, Texas. The experimental design was a randomized complete block, with 4 insecticide treatments and a check replicated 4 times. Cotton was inspected for aphids on 17, 22, and 29 Jul to determine the treatment threshold of �20 aphids per leaf. Ten leaves from the top half and 10 leaves from the lower half of plants from each plot were examined, and the numbers of aphids were counted and recorded on each inspection date. Pre-treatment counts were made and the insecticide treatments were applied on 5 Aug. Treatments were applied with a John Deere High Cycle 6000 sprayer. Spray drops were used to provide 3 nozzles per row, delivering 11.7 total gallons of spray solution per acre at 40 psi. After the application of Fulfill (all replicates), Curacron alone (1st and 3rd replicate) and Curacron + Fulfill + Organosilicant (3rd replicate and one-half of 2nd replicate), it rained hard on the treatment plots. As a result, the spray materials were probably washed off the plants. Also, Curacron foamed badly and sprayer pressure was completely lost; the pressure bypass and agitation system were then turned off to eliminate foaming. Thereafter, all treatments were reapplied on those plots that were sprayed before the rain. Approximately 30 h post-treatment, it rained again 0.38 inches which probably washed the aphids off of the leaves to some degree. Post-treatment aphid counts were made at 3, 7, 13, and 17 DAT. Test plots received additional rainfall on 10 Aug (1.75") and 19 Aug (1.85").