Pupal Counts Research Articles

Aroplectrus dimerus (Hymenoptera: Eulophidae), Ectoparasitoid of the Nettle Caterpillar, Oxyplax pallivitta (Lepidoptera: Limacodidae): Evaluation in the Hawaiian Islands.

The stinging nettle caterpillar, Oxyplax (syn. Darna) pallivitta (Lepidoptera: Limacodidae), is a serious invasive pest of agricultural products and a health hazard on the Hawaiian Islands first discovered in 2001. Nursery workers and homeowners have been stung by the caterpillars while handling their plants, especially rhapis palms (Rhapis sp.). Throughout its invaded range, it causes widespread damage, including the many cultivated and native palm species that have grown in Hawaii. Larvae contain urticating hairs that secrete a toxin, causing painful skin swelling and irritation on contact. Horticulture and nursery products impacted by the limacodid pest are estimated at $84.3 million (2018 value). Suppression efforts with pesticides and lure traps were ineffective, and the moth population continued to spread to major Hawaiian Islands (Hawaii, Kauai, Maui, Oahu). The introduction of specific biological control agents from the native region was thought to be the long-term solution for this invasive pest. Initial exploration in Indonesia and Thailand resulted in the introduction of a pupal ectoparasitoid, Nesolynx sp. (Hymenoptera: Eulophidae: Tetrastichinae), that was not specific. The oriental wasp, Aroplectrus dimerus Lin (Hymenoptera: Eulophidae: Eulophinae), idiobiont gregarious ectoparasitoid of the stinging nettle caterpillar, was introduced from Taiwan in 2004 for host specificity studies and biocontrol in Hawaii. Host range testing showed the parasitoid attacked only limacodid species, and it was approved for field release in 2010. The parasitoid identity, host specificity under containment facility conditions, reproductive performance, and colonization on the major infested sites were assessed. A total of 13,379 parasitoids were colonized on 162 release sites on four Hawaiian Islands. Evaluations were conducted using field surveys of larvae, pupal counts, and male lure traps. Field parasitism was thoroughly investigated on Oahu Island, averaging 18.9 ± 5.6% of 3923 collected larvae during 2010-2023. The numbers of male moths caught/trap/month were significantly reduced on Oahu Island (p < 0.05). Recently, the hyperparasitoid, Pediobius imbreus Walker (Hymenoptera: Eulophidae: Entedoninae), was detected, reducing the efficiency of A. dimerus in the field. The mean hyperparasitism of A. dimerus pupae was 27.3 ± 7.6% on Oahu Island. There was no detailed biological assessment for A. dimerus or its field evaluation available in scientific literature. Results were discussed regarding the potential use of A. dimerus in biocontrol elsewhere if the stinging nettle caterpillar was invaded in the future.

Impact of sowing periods on incidence of stem fly, Melanagromyza sojae (Zehntner) in summer black gram

Six sowing periods during summer (4th week of February, 1st week of March, 2nd week of March, 3rd week of March, 4th week of March and 1st week of April) was evaluated for its impact on incidence of stem fly, Melanagromyza sojae (Zehntner) infesting black gram at Entomology Farm, B. A. College of Agriculture, Anand Agricultural University, Anand. The black gram crop sown during 1st and 2nd week of March exhibited low larval (0.22 and 0.26 /plant), pupal (0.22 and 0.27 /plant) counts of the pest as well as less infestation (28.38 and 29.73%, respectively) and tunnelling (8.92 and 9.45%, respectively) than rest of the sowing periods during summer season. Maximum seed yield was recorded in the crop sown during 2nd week of March (597 kg/ha) followed by 1st week of March (564 kg/ha).

Habitat Characteristics For Immature Stages of Aedes aegypti In Zanzibar City, Tanzania.

Aedesaegypti is the main vector for dengue, chikungunya, yellow fever, Zika, and other arboviruses of public health importance. The presence of Ae. aegypti has never been systematically assessed in Zanzibar, including its preferred larval habitats. In 2016 we conducted a cross-sectional entomological survey to describe the preferred larval habitats of Ae. aegypti in Zanzibar City, the main urban area of the Zanzibar archipelago. The surveys for container habitats were conducted for a 17-wk period beginning in January 2016. Immature stages (larvae and pupae) were collected, reared to adulthood, and identified to species. The positive and potential habitats were categorized on the basis of physical, biological, and chemical parameters. A total of 200 samples were collected, of which 124 (62.0%) were positive for immature stages of mosquitoes and 114 (92%) for Ae. aegypti larvae and pupae. Presence of vegetation (odds ratio [OR] = 2.11, 95% confidence interval [CI] = 1.19-3.74), organic matter (OR = 2.37, 95% CI = 1.21-4.60), inorganic matter (OR = 1.78, 95% CI = 1.01-3.13), and sun exposure (OR = 2.34, 95% CI = 1.24-4.36) were all significantly associated with the presence of immature stages of Ae. aegypti, suggesting that these conditions promote colonization of containers. Plastic containers supported 64% of the immature stages and produced approximately 50% of the pupae. Although immature counts were the highest in discarded artifacts, higher pupal counts were found in domestic water storage containers. Our observations suggest that effective control of Ae. aegypti in Zanzibar City must include improved solid waste management (collection and proper disposal of potential container habitats) and reliable supply of domestic water to minimize water-storing practices that provide larval habitats for Ae. aegypti.

Novel inference models for estimation of abundance, survivorship and recruitment in mosquito populations using mark-release-recapture data.

BackgroundExperiments involving mosquito mark-release-recapture (MRR) design are helpful to determine abundance, survival and even recruitment of mosquito populations in the field. Obstacles in mosquito MRR protocols include marking limitations due to small individual size, short lifespan, low efficiency in capturing devices such as traps, and individual removal upon capture. These limitations usually make MRR analysis restricted to only abundance estimation or a combination of abundance and survivorship, and often generate a great degree of uncertainty about the estimations.Methodology/Principal findingsWe present a set of Bayesian biodemographic models designed to fit data from most common mosquito recapture experiments. Using both field data and simulations, we consider model features such as capture efficiency, survival rates, removal of individuals due to capturing, and collection of pupae. These models permit estimation of abundance, survivorship of both marked and unmarked mosquitoes, if different, and recruitment rate. We analyze the accuracy of estimates by varying the number of released individuals, abundance, survivorship, and capture efficiency in multiple simulations. These methods can stand capture efficiencies as low as usually reported but their accuracy depends on the number of released mosquitoes, abundance and survivorship. We also show that gathering pupal counts allows estimating differences in survivorship between released mosquitoes and the unmarked population.Conclusion/SignificanceThese models are important both to reduce uncertainty in evaluating MMR experiments and also to help planning future MRR studies.

Estimation of Aedes aegypti (L.) (Diptera: Culicidae) productivity in households and public spaces in a dengue endemic city in Colombia

Aedes aegypti is a vector for the dengue virus in Colombia. Its productivity can be estimated using pupal counts. To determine Ae. aegypti productivity in households and public spaces in Girardot (Colombia) during both wet and dry seasons. The amount of Ae. aegypti pupae was evaluated in 20 randomly selected clusters in Girardot, each consisting of 100 households and public spaces. Inspections were performed during the rainy (February-May, 2011), and dry (August-September, 2011) seasons. House, container, Breteau, person and hectare pupae indices were estimated. During the rainy season households contributed 94% to the total number of pupae (n=7,098) while only 6% (n=482) were found in public spaces. In the dry season, 98% (n=9,138) of pupae were found in households and 2% (n=223), in public spaces. Low water-storage tanks and tanks for washing purposes provided >87% of pupae in households, whereas jars, tires and sinks contained most pupae in public spaces. High pupal densities were observed in public spaces during the rainy season and in streets and schools in the dry season. There were no significant differences in the index per person (rainy season=1.0; dry season=1.3) or per hectare (rainy season=0.96, dry season=0.45) between seasons. High Ae. aegypti pupal densities were found inside households in low water-storage tanks and tanks for washing purposes during both the dry and rainy seasons. Public spaces provided more aquatic habitats during the rainy season. Vector control strategies targeting these containers could allow a more rational use of resources and increase efficiency.

Aedes aegypti entomological indices in an endemic area for dengue in Sao Paulo State, Brazil

To evaluate the most productive types of properties and containers for Aedes aegypti and the spatial distribution of entomological indices. Between December 2006 and February 2007, the vector's immature forms were collected to obtain entomological indices in 9,875 properties in the Jaguare neighborhood of Sao Jose do Rio Preto, SP, Southeastern Brazil. In March and April 2007, a questionnaire about the conditions and characteristics of properties was administered. Logistic regression was used to identify variables associated with the presence of pupae at the properties. Indices calculated per block were combined with a geo-referenced map, and thematic maps of these indices were obtained using statistical interpolation. The properties inspected had the following Ae. aegypti indices: Breteau Index = 18.9, 3.7 larvae and 0.42 pupae per property, 5.2 containers harboring Ae. aegypti per hectare, 100.0 larvae and 11.6 pupae per hectare, and 1.3 larvae and 0.15 pupae per inhabitant. The presence of yards, gardens and animals was associated with the presence of pupae. Specific types of properties and containers that simultaneously had low frequencies among those positive for the vector and high participation in the productivity of larvae and pupae were not identified. The use of indices including larval and pupal counts does not provide further information beyond that obtained from the traditional Stegomyia indices in locations with characteristics similar to those of São José do Rio Preto. The indices calculated per area were found to be more accurate for the spatial assessment of infestation. The Ae. aegypti infestation levels exhibited extensive spatial variation, indicating that the assessment of infestation in micro areas is needed.

Ecological Links Between Water Storage Behaviors and Aedes aegypti Production: Implications for Dengue Vector Control in Variable Climates

Understanding linkages between household behavior and Aedes aegypti (L.) larval ecology is essential for community-based dengue mitigation. Here we associate water storage behaviors with the rate of A. aegypti pupal production in three dengue-endemic Colombian cities with different mean temperatures. Qualitative, semi-structured interviews and pupal counts were conducted over a 7-15-day period in 235 households containing a water storage vessel infested with larvae. Emptying vessels more often than every 7 days strongly reduced pupal production in all three cities. Emptying every 7-15 days reduced production by a similar magnitude as emptying <7 days in Armenia (21.9 degrees C), has a threefold smaller reduction as compared to <7 days in Bucaramanga (23.9 degrees C), and did not reduce production in Barranquilla (29.0 degrees C). Lidding vessels reduced mosquito production and was most feasible in Barranquilla because of container structure. Vessel emptying strongly correlated with usage in Barranquilla, where many households stored water in case of interruptions in piped service rather than for regular use. In the cooler cities, >90% of households regularly used stored water for washing clothes, generating a weaker correlation between emptying and usage. Emptying was less frequent in the households surveyed in the dry season in all three cities. These results show that A. aegypti production and human behaviors are coupled in a temperature-dependent manner. In addition to biological effects on aquatic stages, climate change may impact A. aegypti production through human behavioral adaptations. Vector control programs should account for geographic variation in temperature and water usage behaviors in designing targeted interventions.

Eco-bio-social determinants of dengue vector breeding: a multicountry study in urban and periurban Asia

To study dengue vector breeding patterns under a variety of conditions in public and private spaces; to explore the ecological, biological and social (eco-bio-social) factors involved in vector breeding and viral transmission, and to define the main implications for vector control. In each of six Asian cities or periurban areas, a team randomly selected urban clusters for conducting standardized household surveys, neighbourhood background surveys and entomological surveys. They collected information on vector breeding sites, people's knowledge, attitudes and practices surrounding dengue, and the characteristics of the study areas. All premises were inspected; larval indices were used to quantify vector breeding sites, and pupal counts were used to identify productive water container types and as a proxy measure for adult vector abundance. The most productive vector breeding sites were outdoor water containers, particularly if uncovered, beneath shrubbery and unused for at least one week. Peridomestic and intradomestic areas were much more important for pupal production than commercial and public spaces other than schools and religious facilities. A complex but non-significant association was found between water supply and pupal counts, and lack of waste disposal services was associated with higher vector abundance in only one site. Greater knowledge about dengue and its transmission was associated with lower mosquito breeding and production. Vector control measures (mainly larviciding in one site) substantially reduced larval and pupal counts and "pushed" mosquito breeding to alternative containers. Vector breeding and the production of adult Aedes aegypti are influenced by a complex interplay of factors. Thus, to achieve effective vector management, a public health response beyond routine larviciding or focal spraying is essential.

Development of a Combined Sex Pheromone-based Monitoring System forMalacosoma disstria(Lepidoptera: Lasoicampidae) andChoristoneura conflictana(Lepidoptera: Tortricidae)

Sympatric insect species that do not share sex pheromone components but have a common host and overlapping adult flight periods are potential targets for the development of a combined sex pheromone-based monitoring tool. A system using a single synthetic pheromone blend in a single lure to bait a single trap to monitor two pests simultaneously represents a novel approach. In this study, a combined pheromone-based monitoring system was developed for two lepidopterous defoliators of trembling aspen Populus tremuloides Michenaux in western Canada, Malacosoma disstria Hübner (Lepidoptera: Lasoicampidae) and Choristoneura conflictana (Walker) (Lepidoptera: Tortricidae). Efficacy and longevity of a lure containing both species' pheromones were tested. Immature stages of each species were sampled to evaluate the ability of pheromone traps baited with the combined lure to predict population density. The combined lure was as attractive to M. disstria and C. conflictana males as were traps baited with each species' pheromone alone. Lure age had no effect on attraction of male C. conflictana to the combined lure but had a negative effect on attraction of M. disstria. The number of male moths captured in traps baited with the combined lure was related to immature counts for both species. Pupal counts of M. disstria and larval counts of C. conflictana provided the best relationships with male captures. The combined lure does not attract M. disstria males in direct proportion to population density, because trap catch was comparatively low at high-density M. disstria sites.

The effect of shade on the container index and pupal productivity of the mosquitoesAedes aegyptiandCulex pipiensbreeding in artificial containers

The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of < 6 L (flower vases) were the predominant breeding habitats, to compare various measures of the productivity of sunlit and shaded containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P < 0.001]; Cx pipiens: 6.3% vs. 1.8% [chi(2) = 24, P < 0.001]). However, the number and the density of immatures per infested container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae. aegypti and approximately 1059 in the middle of January for Cx pipiens. Spearman's correlations between monthly total productivity and monthly CI were significant at P < 0.001 for Ae. aegypti (r(s) = 0.975) and P < 0.01 for Cx pipiens (r(s) = 0.869). Our findings indicate that the efficacy of control campaigns against the two most important mosquito vectors in temperate Argentina could be improved by targeting containers in shaded areas, with maximum effort during species-specific times of year when pupal productivity is at its peak.

USE OF THE PUPAL SURVEY TECHNIQUE FOR MEASURING AEDES AEGYPTI (DIPTERA: CULICIDAE) PRODUCTIVITY IN PUERTO RICO

The hypothesis tested was that most pupae of Aedes aegypti are produced in a few types of containers so that vector control efforts could concentrate on eliminating the most productive ones and thus prevent dengue outbreaks. Pupal surveys were conducted twice in 2004 in an urban area in southern Puerto Rico. A total 35,030 immature mosquitoes (III and IV instars, pupae) was counted in 1,367 containers found with water in 624 premises during the first survey. Only pupae were counted in the second survey in 829 premises, 257 of which had containers with water, and 124 contained Ae. aegypti pupae (15%, 22% in the first survey). We found fewer (583) containers with water than in the first survey, but 202 had pupae (35%; 18.5% in first survey). Containers yielded 3,189 Ae. aegypti pupae, which was slightly fewer than those found in the first survey (3,388 pupae). The hypothesis was supported by the data, showing that 7 of 18 types of containers contained 80% of all female pupae. The most productive containers generally were also common. We used several criteria (i.e., container use, two-step cluster analysis based on environmental variables of containers and premises) to classify the containers and premises and to evaluate pupal distribution at various spatial scales (container, premise, and residences versus public areas). Most pupae were in 4 of 10 types of container usage categories. The cluster technique showed that most pupae were in unattended, rain-filled containers in the yards, particularly in receptacles in the shade of trees that received rainfall through foliage and had lower water temperatures. Pupal counts were adjusted to a negative binomial distribution, confirming their highly aggregated dispersal pattern. Cluster analysis showed that 61.3% of female pupae were in 40 (6.4%) of 624 premises that had in common their larger yards, number of trees, and container water volume. Using number of Ae. aegypti larvae, Breteau Index, or the presence of immature forms as indicators of pupal productivity is not as efficient in identifying the most productive types of containers as direct pupal counts.

Temporal and Geographic Patterns of &lt;I&gt;Aedes aegypti&lt;/I&gt; (Diptera: Culicidae) Production in Iquitos, Peru

Large-scale longitudinal cohort studies are necessary to characterize temporal and geographic variation in Aedes aegypti (L.) (Diptera: Culicidae) production patterns and to develop targeted dengue control strategies that will reduce disease. We carried out pupal/demographic surveys in a circuit of approximately 6,000 houses, 10 separate times, between January 1999 and August 2002 in the Amazonian city of Iquitos, Peru. We quantified the number of containers positive for Ae. aegypti larvae and/or pupae, containers holding pupae, and the absolute number of pupae by 4-mo sampling circuits and spatially by geographic area by using a geographic information system developed for the city. A total of 289,941 water-holding containers were characterized, of which 7.3% were positive for Ae. aegypti. Temporal and geographic variations were detected for all variables examined, and the relative importance of different container types for production of Ae. aegypti was calculated. Ae. aegypti larvae and pupae were detected in 64 types of containers. Consistent production patterns were observed for the lid status (lids: 32% wet containers, 2% pupal production), container location (outdoor: 43% wet containers, 85% pupal production), and method by which the container was filled with water (rain filled: 15% wet containers, 88.3% pupal production); these patterns were consistent temporally and geographically. We describe a new container category (nontraditional) that includes transient puddles, which were rare but capable of producing large numbers of pupae. Because of high variable pupal counts, four container categories (large tank, medium storage, miscellaneous, and nontraditional) should be targeted in addition to outdoor rain-filled containers that are not covered by a lid. The utility of targeted Ae. aegypti control is discussed, as well as the ability to achieve control objectives based on published but untested threshold values.

Influence of burlap-band colour on larval, pupal, and egg-mass counts of Lymantria dispar (Lepidoptera: Lymantriidae)

AbstractThis paper describes the effect of the colour of burlap bands (black versus naturally coloured or tan burlap) affixed to red oak, Quercus rubra (L.) (Fagaceae), and how it influences selection of larval resting site, pupation site, and egg-mass counts of gypsy moth, Lymantria dispar (L.). In field experiments with half black and half tan burlap bands, the mean number of larvae, pupae, and egg masses were significantly greater under the black section of burlap. Individual burlap bands composed of either black or tan burlap affixed to separate trees produced similar significant results for larvae and pupae. When two burlap bands composed of opposite colours (black versus tan) were affixed to the same tree, significantly more larvae were found under the upper band, regardless of colour. In contrast, pupa and egg-mass densities were significantly greater under black bands, regardless of band position.

Identifications of two different mechanisms for sorghum midge resistance through QTL mapping.

Sorghum midge is the one of the most damaging insect pests of grain sorghum production worldwide. At least three different mechanisms are involved in midge resistance. The genetic bases of these mechanisms, however, are poorly understood. In this study, for the first time, quantitative trait loci associated with two of the mechanisms of midge resistance, antixenosis and antibiosis, were identified in an RI (recombinant inbred) population from the cross of sorghum lines ICSV745 x 90562. Two genetic regions located on separate linkage groups were found to be associated with antixenosis and explained 12% and 15%, respectively, of the total variation in egg numbers/spikelet laid in a cage experiment. One region was significantly associated with antibiosis and explained 34.5% of the variation of the difference of egg and pupal counts in the RI population. The identification of genes for different mechanisms of midge resistance will be particularly useful for exploring new sources of midge resistance and for gene pyramiding of different mechanisms for increased security in sorghum breeding through marker-assisted selection.

DENGUE AND ITS VECTORS IN THAILAND: CALCULATED TRANSMISSION RISK FROM TOTAL PUPAL COUNTS OF AEDES AEGYPTI AND ASSOCIATION OF WING-LENGTH MEASUREMENTS WITH ASPECTS OF THE LARVAL HABITAT

Working in a village dengue focus in Chachoengsao Province, Thailand, aedine mosquito larvae and pupae were counted in all containers of 10 houses per month. The wings of female Aedes aegypti (L.) emerging from pupae were measured. Number of pupae and size of emerging females increased in containers with qualities that favored availability of larval food sources (e.g., uncovered containers). The small size of most mosquitoes compared with those raised in the laboratory indicated that the larval population as a whole was under nutritional stress. Applying the number of pupae per house and measurement of air and water temperature with an existing model, the risk of dengue transmission was greatest in May and June. The estimated number of female Ae. aegypti per house was well above the threshold for increasing transmission in all months but December through February. A phased approach to sampling immature aedine mosquitoes in Thailand is proposed, which would consist of routine surveillance of larval index and occasional total counts with measurement of wing size. Such a system would combine the benefits of the simple application of larval surveillance with the valuable data gathered from pupal counts and wing measurements.

Application of synthetic sex pheromone for management of diamondback moth, Plutella xylostella, in cabbage

AbstractOver a 2‐year period field trials were conducted to assess the potential to disrupt mating ofPlutella xylostella (L.) using a commercial rope formulation of a 70:30 mixture of (Z)‐11‐hexadecenal and (Z)‐11‐hexadecenyl acetate, two components of the sex pheromone of the female. Screened field cages were placed into blocks of cabbage which were either treated with the pheromone or left untreated. Different densities of P. xylostella pupae were placed into each cage and then larval and pupal counts were made of the subsequent generation. In addition, sentinel females at mating stations were placed in each cage to assess the influence of the pheromone on the ability of males to locate and mate with females. Likewise, we used pheromone traps to assess whether the pheromone treatment influenced the ability of males to locate a pheromone source. In both years larval and pupal populations, produced as a result of the original inoculation, did not differ between pheromone‐treated and untreated fields. The effect of pheromone treatment on larval and pupal numbers did not change with changes in inoculated P. xylostella density, however, the density of P. xylostella released caused significant differences in the density of the subsequent generation. No significant differences were detected between the number of sentinel female adult P. xylostella that successfully mated in pheromone‐treated fields compared with untreated fields. Significant differences in the numbers of male P. xylostella caught in pheromone‐baited traps occurred between pheromone‐treated and untreated fields in the first trial of 1993, and in the first trial in 1994 but not in the second trial. Such differences are often thought of as indications of mating disruption, although our other data presented in this study and reports from other studies indicate this is not always the case. Previous studies on mating disruption of P. xylostella in larger scale field tests have been performed but the results have been variable and often ambiguous. Overall, our results indicate that mating disruption of P. xylostella with the present technology does not appear to work even under the very controlled situations which we utilized to eliminate insect movement between plots.

Peach, Control of Peachtree Borers with Chemical Insecticides, 1996

Abstract Treatments were applied during the late summer of 1995 to mature (greater than 15 year old) Autumhglo peach trees in a commercial orchard. Most trees had heavy gumming at the base, showing symptoms of prolonged borer activity. Treatments were arranged in a RCB design with 4 replicates, 10 trees per replicate for a total of 40 trees per treatment. Applications were made with a Durand Wayland 100 gal. handgun sprayer set at 250 psi. Applications were made on 11 Aug and 26 Sep, and applied to the base of each tree with 1.25 gal of spray volume per tree. Pupal cases were counted on each tree on 6 Sep and 26 Oct, 1995, and again on 7 Aug, 12 Sep and 1 Oct, 1996. Pupal case counts were combined to give yearly totals.

Effect of Insecticides on Celery Insectsc, 1995

Abstract Celery was transplanted in a sandy loam soil on 29-30 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a RCB design. Applications were weekly from 5 Oct through 30 Nov (total of 9 applications for all chemicals except Avid and Avid + Lannate). Actual dates of applications were: 5, 12, 19, 26 Oct, and 3, 9, 16, 21, 30 Nov. Avid was applied on 5, 12 Oct and again on 3, 9, 30 Nov. The Avid + Lannate treatment was the same except that Lannate was applied on 19, 26 Oct and 16, 21 Nov. All chemicals were applied by a tractor-mounted boom sprayer operated at 125 psi. Nozzles were 4 per bed and carrier (H2O) was at 100 gpa. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5 1/2 X 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 16, 25, 31 Oct and 8, 16, 20, 30 Nov. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of BAW populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (6-7 Dec).

Impact of Insecticides on Celery Insects, 1994

Abstract Celery was transplanted in a sandy loam soil on 30-31 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Applications were weekly from 6 Oct through 21 Nov (total of 8 applications for all chemicals except Avid and Avid + Xentari). Actual dates of applications were: 6, 13, 20, 27 Oct, and 3, 10, 17, 21 Nov. Avid was applied on the first two dates and again for dates 5-6. The Avid + Xentari treatment was the same except that Xentari was applied on dates Avid was not. All chemicals were applied by a tractor-mounted boom sprayer operated at 125 psi. Nozzles were 4 per bed and carrier (H2O) was at 100 gal/ac. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5 ½ X 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 15, 25 Oct and 1, 8, 15, 21, 28 Nov. The number of dead adult parasites of1 Liriomyza species was recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (29-30 Nov). Beet armyworm and black cutworm damage were recorded separately.

Predictive Capabilities of a Pheromone-Based Monitoring System for Western Hemlock Looper (Lepidoptera: Geometridae)

Eggs, larvae, and pupae of the western hemlock looper, Lambdina fiscellaria lugubrosa (Hulst), were sampled and related to the numbers of male moths captured in pheromone-baited Unitraps at 27 (1992) and 34 (1993) study sites throughout the coastal western hemlock and interior cedar hemlock biogeoclimatic zones of British Columbia. Male moth catches in traps baited with 10 μg of both isomeric 5,1l-dimethylheptadecane and 2,5-dimethylheptadecane on a rubber septum lure were significantly correlated with larval and pupal counts within the same generation and were predictive of egg counts in the subsequent generation, suggesting that pheromone-baited traps could be used to monitor populations and predict future outbreaks.