Pest Of Pears Research Articles

Attraction of male summerform pear psylla to volatiles from female pear psylla: effects of female age, mating status, and presence of host plant

AbstractPear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), is a pest of pears, Pyrus L. (Rosaceae), throughout North America and western Europe. Previous studies in our laboratory showed that males of the overwintering form (winter morphotype) were attracted to volatile chemicals from pear shoots infested with post-diapause females. The current study shows that males of the summer morphotype also are attracted to volatiles from female-infested host material. Older females (8–10 d old) were significantly more attractive to males than younger (2–5 d old) females. Both virgin and mated females attracted male psylla. Volatiles from female summerforms attracted males even in the absence of host-plant material, and both living and freshly killed females were attractive. Our results indicate that female C. pyricola emit a volatile sex attractant, and the results of the studies further define the life-history conditions in female pear psylla that lead to male attraction.

Preliminary Resistance Screening on Abamectin in Pear Psylla (Hemiptera: Psyllidae) in Northern Italy

In northern Italy (Emilia-Romagna region), integrated pest management has been used for several years against pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), a relevant pest of pear (Pyrus spp.) trees. After the outlawing of amitraz in 2005, the most common active ingredient involved is abamectin, a mixture of avermectin B1a and avermectin B1b. After the development of C. pyri resistance to azinphos methyl in southern France, we evaluated, by topical application, the different sensitivities to abamectin on C. pyri populations collected in orchards from Emilia-Romagna, where different field strategies were used, with alternative success in terms of pest management. The LC50 values ranged between 1.61 and 28.37 mg/liter, and they revealed variations more related to collection time than to field strategies. The failure of abamectin treatments against C. pyri in some Emilia-Romagna locations is probably unrelated to resistance development, but rather it is related to incorrect pest defense management, which could interfere with pest parasitoids and predators.

Oviposition deterrency and deterrent stability of some oily substances against the pear psyllaCacopsylla pyri

Oviposition deterrents have the potential to prevent insect infestations in agroecosystems. In the present study, the level and duration of this behavioral effect was evaluated against pear psylla,Cacopsylla pyri (L.) (Hemiptera: Psyllidae), a serious pest of pears in Turkey. The activity of four oily substances — cotton seed oil, fish-liver oil, neem oil and summer oil — was tested against winterform and summerform females of the pest in laboratory and field experiments, in order to determine their oviposition deterrency and stability as deterrents. In the laboratory assays, the initial (3 days after treatments) deterrency of all test materials was 100%. While decreases in initial deterrency started after 1 week for neem oil and after 2 weeks for cotton seed oil, fish-liver oil and summer oil exhibited 100% deterrent activity against winterforms, but not summerforms during the 3-week test period. The last two also exhibited strong oviposition deterrent activity for both forms ofC. pyri females in field trials. A significant reduction in the total number of eggs laid was observed in the field plots. Data showed that summer oil and fish-liver oil are the most promising oviposition deterrents against pear psylla females.

Detecting Cacopsylla pyricola (Hemiptera: Psyllidae) in predator guts using COI mitochondrial markers.

Cacopsylla pyricola (Förster) is one of the most important pests of pear in North America, where several native predators have been considered for integrated pest management (IPM) programmes. Two molecular markers of 271 and 188 bp were developed from C. pyricola cytochrome oxidase I (COI) fragments, in order to study the detection of this species in the gut of arthropod predators. Primer sensitivity and the detection period for pear psylla remains in the guts of Anthocoris tomentosus Pericart were determined. The sensitivity threshold was defined at 10-5 dilution of a C. pyricola fifth-instar nymph in all samples. Predator adults were evaluated immediately after ingestion of one to five C. pyricola nymphs (t = 0) and after 2, 4, 6, 8, 16, 24 and 32 h. Detection of the presence of C. pyricola DNA always lasted longer using the shorter fragment and was observed after 32 h of digestion using both markers. The primers amplifying the 188 bp fragment amplified all four psyllid species tested, whereas the primers designed to amplify the 271 bp fragment did so exclusively for C. pyricola and its close relative, Cacopsylla pyri (Linnaeus). Both primers failed to amplify DNA from representative species of the Coccinellidae, Chrysopidae, Hemerobiidae, Anthocoridae, Miridae, Salticidae, Aphididae, Tetranychidae and the Tortricidae, suggesting their suitability for general trophic studies.

Biocontrol of Pests of Apples and Pears in Northern and Central Europe - 3. Predators

Predators of apple and pear pests in northern and central Europe and their use as biological control agents are reviewed. Many natural enemy species are specialized feeders and are able to respond to the population dynamics of particular pest species. The most oustandingly successful example of this is the use of phytoseiid mites, particularly Typhlodromus pyri , against phytophagous pest mites in apple. This mite management strategy is now widespread throughout European apple growing regions. Another example is the use of Anthocoris nemoralis against pear psyllids, Cacopsylla pyricola and C. pyri . Several groups of naturally occurring polyphagous predators, such as chrysopids, coccinellids, syrphids and spiders, also prey on a number of pest species in orchards, contributing generally to the reduction in pest populations. However, they are unlikely alone to prevent pest damage fully and reliably. In seeking biological control opportunities for a particular pest, these polyphagous natural enemies are unlikely to be a high priority. An exception, due to its abundance in orchards, is the common earwig, Forficula auricularia , although this predator may also cause some fruit injury. Another option to consider when reviewing possibilities for biological control in orchards is the introduction of biological control agents. The success rate of this approach, using arthropod predators to control pests of field crops, has been generally poor. Furthermore, mass production methods for predators are likely to be difficult and very costly. The biological supplies industry is constantly seeking culture techniques, largely for arthropod biological control agents of pests of protected crops. It is possible that some future advance may be relevant to orchards, though currently available predators do not appear promising. A careful economic appraisal of the feasibility of use of any potential biological control agent would be prudent before embarking on research.

Progress Toward Liquid Formulations of Particle Films for Insect and Disease Control in Pear

Particle film technology is aimed at controlling both arthropod pests and diseases of plants with a hydrophobic particle barrier primarily composed of kaolin. Field studies were conducted from 1996 to 1998 to compare the efficacy of dust and liquid applications, and hydrophobic and hydrophilic particle films, against key pests of pear. In addition, the effects of particle film applications on pear yield and quality were investigated in 1998. Dust and liquid applications of hydrophobic and hydrophilic particle films obtained high levels of early-season pear psylla control and prevented pear rust mite damage. We also found that prior seasonal applications of particle films in 1997 can carry over into the 1998 season to suppress early season pear psylla oviposition. A major concern in the shift from hydrophobic to hydrophilic particle films was the loss of disease control. We found that a water-repellant particle film was not required to control the fungal disease fabraea leaf spot. Pear yields were nearly doubled by liquid formulations of hydrophobic and hydrophilic particle films. Particle film deposits were measured using a spectrophotometer method we developed. Particle deposition differed among formulations for both leaf age and leaf surface (top or bottom). Yet, the particle formulations performed about the same against insects and fungal diseases, and in how they influenced the horticultural traits. None of the particle film formulations were found to be phytotoxic to pear foliage or fruit during the study period. A shift from hydrophobic to hydrophilic particles makes it possible to more easily formulate and disperse the particles in water so that conventional spray equipment can be used. The multifunctionality and low toxicity of particle films could make them an attractive alternative to conventional pesticides.

Biocontrol of Pests of Apples and Pears in Northern and Central Europe: 2. Parasitoids

The parasitoids of arthropod pests of apple and pear in northern and central Europe and their use as biological control agents are reviewed. The review demonstrates that apple and pear pests are host to a large and varied parasitoid fauna. All important pests are known to be host of parasitoids, but many parasitoids play only a minor part in regulating populations of their host. However, many parasitoid species are important natural enemies and some effectively regulate pest populations in unsprayed and/or commercial (insecticide sprayed) apple or pear orchards either individually or as part of parasitoid guilds. Exploitation/fostering of existing populations of parasitoids has been demonstrated to be an effective or partially effective approach for natural control of several important pest species. Important examples include natural regulation of the apple sawfly by Lathrolestes ensator and Aptesis nigrocincta, of the summer fruit tortrix moth by Colpoclypeus florus and Teleutaea striata, of leaf midges by Platygaster demades, of woolly aphid by Aphelinus mali and of leaf mining moths by guilds of parasitoid species. Introduction of parasitoids is an alternative approach to the exploitation of parasitoids already present in the orchard. This approach has been little explored and its success rate has been low, mainly confined to the control of non-indigenous pests by introducing parasitoids from their native region. Mass production methods for parasitoids are difficult and costly and are likely to be economic only where long-term populations can be established. Even where low cost mass culture techniques are developed, the degree of control may not be high enough to prevent economic pest damage as demonstrated by negative results with mass release of Trichogramma egg parasites for control of tortricids in orchards. Suitability of the orchard habitat is recognized as crucial to the success of individual parasitoids. Key requirements are adequate populations of the pest(s) and/or alternative hosts, suitable shelter, overwintering sites or food sources and avoidance of harmful effects of pesticides. Many species are highly sensitive to broad-spectrum insecticides, especially in the adult life-stage. Avoiding the harmful affects of insecticides is crucial to successful exploitation. The use of insecticides needs to be avoided, either altogether or at crucial times in the parasitoids' life cycle, or less harmful alternatives need to be used. Numerous parasitoids could potentially be exploited as biological control agents but hitherto have received little attention because little is known about them and/or because they are sensitive to broad-spectrum pesticides and are thus virtually absent from commercial orchards. The aim of future studies should be to develop effective strategies for establishing equilibria between important pests and their parasitoids, with pest damage rarely exceeding the economic threshold.

Biocontrol of Pests of Apples and Pears in Northern and Central Europe: 1. Microbial Agents and Nematodes

The viral, bacterial, fungal and nematode pathogens of arthropod pests of apple and pear in northern and central Europe and their use as biocontrol agents are reviewed. Baculoviruses are important viral pathogens of several lepidopterous pests of apple and pear but other viral pathogens have not been investigated in depth and are little known. The granuloviruses of codling moth, Cydia pomonella (CpGV), and to a lesser extent, of the summer fruit tortrix moth, Adoxophyes orana (AoGV), have been researched extensively and are exploited as biological control agents. Commercial development and use has been limited because of their high costs, slow action, short persistence and specificity relative to broad-spectrum pesticides. The widespread development of strains of codling moth multi-resistant to insecticides and the desire to reduce dependence on pesticides have improved the commercial prospects of CpGV and use is likely to increase. The development of a genetically improved egt-strain of CpGV (lacking the ecdysteroid-UDP glucosyl transferase gene) in the UK is a significant breakthrough, though commercialization in the UK may be difficult due to adverse public attitudes to the release of genetically-modified microorganisms. Future research and development approaches include further genetic manipulation of CpGV and AoGV to improve potency, speed of kill and/or persistence, improvement of formulation (to reduce UV light sensitivity) and development of cheaper mass production techniques and possibly in vitro production. A systematic search for baculoviruses and other viruses of apple and pear pests is likely to reveal important new opportunities. The most important bacterial pathogen used as a biological control agent is Bacillus thuringiensis (Bt). However, Bt products currently available have limited effectiveness against many orchard pests due to the pests' cryptic life habits. The HD-1 Bt strain has been investigated and used extensively for control of leaf-rolling tortricid larvae and is widely used, but efficacy is moderate. Advances in biotechnology and genetic engineering provide opportunity for development of Bt strains designed specifically to control orchard pests, but this has not yet been done for commercial reasons. Other research approaches include the evaluation of new Bt products developed for other markets worldwide and the bioassay of strains from Bt collections against specific apple or pear pests. Entomopathogenic fungi provide good opportunity for development as biological control agents of apple and pear pests. The main factor limiting their effectiveness is the requirement for high humidities and moderate temperatures for spore germination and development. For foliar pests, a useful starting point for research might be the control of sucking pests which excrete honeydew (e.g. Cacopsylla sp. or aphids) or those that inhabit protected microenvironments (e.g. Dasineura sp.). Key areas for research are improved formulation, the selection of low temperature-active strains, field evaluation and avoiding possible adverse effects of fungicides. An alternative approach is to examine the exploitation of entomopathogenic fungi in soil, to which many species of entomopathogenic fungi are adapted ecologically. Apple and pear orchards provide long-term stable habitats where populations of entomopathogenic fungi in soil are likely to be large. There are few important soil pests of apple or pear. However, many species spend part of their life in soil, mainly to pupate or overwinter, where they may be targeted by fungal entomopathogenic biocontrol agents. Entomopathogenic nematodes have many attributes which favour them as biological control agents. However, their requirement for surface moisture for survival and movement means there are only limited prospects for using them as biological control agents for foliar pests. As with entomopathogenic fungi, there are better prospects for control of pests that occur in soil. Microbial pathogens and entomopathogenic nematodes are important components of the natural enemy complex of apple and pear orchards and more effort needs to be devoted to fostering them and exploiting them as biocontrol agents in sustainable, biologically-based Integrated Pest Management programmes. They can in many cases be mass produced at low cost by bulk fermentation processes and applied as sprays (as 'biopesticides') and are, at least potentially, ideal biological control agents for many apple or pear pests. Important general characteristics are their comparative environmental and human safety, compatibility with other control strategies in Integrated Pest Management programmes and reproductive capacity. They tend to be effective in a narrower range of environmental conditions than pesticides, but there is considerable potential to improve their effectiveness by improved formulation, strain selection and genetic manipulation. They are often host-specific and thus, offer restricted marketing opportunities, which is a significant barrier to development and commercialisation. Registration procedures and associated fees for microbial agents are a further significant barrier. Such requirements do not apply currently to nematodes.

Fungal pathogens for arthropod pest control in orchard systems: mycoinsecticidal approach for pear psylla control

This paper reviews the research on entomopathogenic fungi in orchard systems and presents research on a mycoinsecticidal approach to an important pest of pear, the pear psylla. The review identifies the host-pathogen relationships that have been examined to date, the microbial formulation and application strategies that have been used, and the results that were obtained. The mycoinsecticides used in the pear psylla research were based on conidia of Beauveria bassiana (ARSEF #2860) and Paecilomyces fumosoroseus (ARSEF #2658). These were formulated into sprayable solutions containing water, 0.1% or 0.5% Ultrafine Sunspray oil (paraffinic oil) in water, or 0.1% acrylic polymer (StressguardTM) in water. Final spray solutions that contained 6 × 106 conidiospores/ml were applied to psylla nymph infested trees at a rate of 5.39 × 1013 conidiospores/ha during the 1993--1995 seasons. In addition, two commercial formulations of B. bassiana, GHA from Mycotech and Naturalis L from Fermone Corp., were mixed in water at the same conidiospore application rates as the other fungal isolates. Single applications of the ARSEF fungal strain/formulation combinations produced psylla nymphal mortalities that ranged from 18.2--37.1%, but the results varied with formulation. Conidia formulated with acrylic polymers in water caused significantly higher mortalities several days earlier than either the water or water and oil combination in 1993. However, no significant differences among pathogen/formulation combinations occurred in 1994 or 1995. The performance of Naturalis L was comparable to the ARSEF fungal strain/formulation combinations with peak nymphal mortalities of 34.1%, while GHA produced a significantly lower peak mortality of only 10.8%. However, because of the low conidiospore concentrations in the Naturalis L formulation, final spray solutions contained nearly 25% of the oil-like carrier. Thus, psylla mortalities may not have been entirely attributed to mycosis. Based on the results from the ARSEF fungal formulations, a mycoinsecticidal approach to pear psylla management could be a useful component in an integrated pest management program for pear.

Diflubenzuron-Based Management of the Pear Pest Complex in Commercial Orchards of the Hood River Valley in Oregon

In the Hood River Valley of Oregon, a pear pest management program based on the insect growth regulator, diflubenzuron, was compared with conventional programs based on broad-spectrum pesticides during 1987-1989. Diflubenzuron-based programs allowed for the immigration and development of natural enemies of the pear psylla, Cacopsylla pyricola Forster. In 13 of 14 comparisons, natural enemies were more abundant in diflubenzuron-based plots than in conventional plots, but additional psyllacides were almost always required to prevent unacceptable fruit damage. Psylla densities were determined by both pesticide applications and seasonal predator-prey interactions. Psylla densities were lower in plots where a light oil was added to the first 2 diflubenzuron applications. Codling moth, Cydia pomonella (L.), were suppressed effectively in both diflubenzuron-based and conventional plots. Miticides were frequently required in all plots, conventional or otherwise, but mites were suppressed best in plots where diflubenzuron with oil was applied. Densities of predatory mites were low at all sites during all years.

Effect of Leaf Age on Length of Residual Activity of Abamectin in Pome Fruit Foliage

The hypothesis that leaf age at time of application influenced absorption of abamectin and hence length of residual control was tested using field-aged residues in laboratory bioassays with twospotted spider mite, Tetranychu. S urticae Koch, on apple and pear foliage. Comparison was made with fenbutatin-oxide residues on apple foliage. Applications were made to 2-, 6-, or 12-wk-old leaves. On apple, initial mortality and the length of residual control by abamectin was highest for applications to younger leaves. The rate of decline in residual activity against T. urticae was steepest in the oldest leaves. With fenbutatin-oxide, leaf age did not affect initial activity, although the rate of decline in activity was higher when applied to older leaves. However, applications to older leaves coincided with weather conditions most likely to break down surface deposits of this material. On pear, initial residual activity for abamectin was lower in older leaves, but the rate of decline in activity was similar for all leaf ages. Overall, initial mortality and length of residual control were higher on pear than on apple, but best performance on both crops was obtained by applications to younger leaves. Implications for use of abamectin in apple and pear pest management programs are discussed.

PEST‐MAN: a forecasting system for apple and pear pests1

To achieve satisfactory management of insect pests of apple and pear, growers must accurately establish the necessity for control actions such as supplementing natural enemy numbers or applying pesticides, and the optimal timing for these actions. Inaccurate determination of these questions can lead to unnecessary or inefficient actions being taken, with undesirable environmental and financial consequences. A project, funded by the British Apple and Pear Research Council, began in 1988 to describe mathematically the population dynamics and phenology of several apple and pear pests. The objective of the research was to develop a suite of simulation models to be used in conjunction with automatic meteorological monitoring equipment to provide a rational basis for decision making in pest management. The models have been thoroughly validated using historical results of pest populations in orchards in south‐east England. Output from the models has been satisfactorily accurate, and as a result a delivery system for the models has been developed. This package, named PEST‐MAN, has an intuitive style of presentation involving simple pull‐down menus, context‐sensitive help statements and colour graphics, and allows users to familiarize themselves quickly with the system.

Pear, Insecticide Evaluations, 1992

Abstract Mature ‘Bartlett’ pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 single-tree replicates in randomized block design. All treatments except Agridyne and NTN 33893 at 6.7 oz were applied 23 Apr, 19 May and 20 Jul. Agridyne was applied 23, 30 Apr, 7 May and 1, 8, 15 Jun. NTN 33893 at 6.7 oz was applied 23 Apr and 19 May. Treatments were evaluated for PP control by counts made at 2-wk intervals. Adult PP were counted from a 5-beating-tray sample per replication. PP nymphs were counted from a 25-leafsample per replicate. Samples prior to 26 May consisted of fruiting spur leaves, those during the remainder of the season consisted of the proximal leaf, distal leaf and 3 leaves from the middle of 5 terminal shoots. Leaves were brushed and resulting slides were examined under 10 X magnification. Fruit damage by insects and mites was rated according to US grade standards for fresh market ‘Bartlett’ pears on 2 samples of 25 mature fruits per replication. Factors of fruit quality including firmness, soluble solids and size were evaluated from 2 10-fruit samples per replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicity after each spray.

Pear, Soft Pesticide Test, 1991

Abstract 'Bartlett' and 'Anjou' pears were sprayed with handgun or airblast equipment to compare seasonal programs of soft pesticides for control of insect and mite pests of pear and survival of beneficial arthropods. Plots consisted of 3 30-tree replicates in 3-row blocks. An untreated check was also included in the randomized block design. PP adults, PP predators, and parasite, Trechnites insidiosus, densities were monitored by limb-taps. PP nymphs were counted on 50-leaf samples per replication. Samples for first generation nymphs were collected from fruiting spurs, those for second and subsequent generations were collected from growing shoots. The proximal leaf, distal leaf, and 3 leaves from the middle were picked from each of 10 shoots. Leaves were processed with a leaf brushing machine and PP nymphs and mites were counted on 20% of the resulting slides under 10 x magnification. Pest damage to fruit was determined by examining 50 fruit per replication at harvest. Fruit firmness, size, and soluble solids content were compared on 2 10-fruit samples per replication. Treatment histories for the 3 programs are presented in the table.

Pear, Insecticide Evaluations, 1991

Abstract Mature 'Bartlett' pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 single-tree replicates in randomized block design. All treatments were applied 2 May and 26 Jun. Cold Power and Ray-Gard were also applied 10 May, 23 May, and 25 Jul. Treatments were evaluated for PP control by counts made at 2-wk intervals. Adult PP were counted from a 5 beating-tray sample per replication. PP nymphs were counted from a 50-leaf sample per replicate. Leaf samples consisted of the proximal leaf, distal leaf and 3 leaves from the middle of 10 terminal shoots. Leaves were brushed and resulting slides were examined under 10 × magnification. Fruit damage by insects and mites was rated according to US grade standards for fresh market Bartlett' pears on 2 samples of 25 mature fruit per replication. Factors of fruit quality including firmness, soluble solids, and size were evaluated from 2 10-fruit samples per replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicity after each spray.

Pear, Insecticide Evaluations, 1990

Abstract Mature 'Bartlett' pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 single-tree replicates in randomized block design. Application dates varied between treatments and are given in the table of adult count data. Treatments were evaluated for PP and mite control by counts made at 2-wk intervals. Adult PP were counted from a 5 beating-tray sample/replication. PP nymphs and phytophagous mites were counted from a 50-leaf sample/replicate. Leaf samples consisted of the proximal leaf, distal leaf and 3 leaves from the middle of 10 terminal shoots. Leaves were brushed and resulting slides were examined under magnification. PP russet was rated according to US grade standards for fresh market 'Bartlett' pears on 2 samples of 25 mature fruits/replication. Factors of fruit quality including firmness, soluble solids and size were evaluated from 2 10-fruit samples/replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicity after each spray.

Pear Psylla Control with S 71639, 1990

Abstract Eleven-yr-old pear 'Bartlett' and 'Anjou' trees were sprayed with handguns operating at 600 psi to evaluate S 71639 for control of pear pests. Plots consisted of 2 replicates of 6 × 6 tree rectangles. Treatments were evaluated for PP and PRM control by counts made at 2-wk intervals. Adult PP were counted from a 25-beating-tray sample/replication. PP nymphs and PRM were counted from 2 50-leaf sample/ replicate. Leaf samples consisted of the proximal leaf, distal leaf and 3 leaves from the middle of 10 terminal shoots. Leaves were brushed and resulting slides were examined under magnification. PP russet and other pest damage were rated according to U.S. grade standards for fresh market pears on 100 mature fruits/cultivar/replication. Factors of fruit quality including firmness, soluble solids and size were evaluated from 2 10-fruit samples/replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicity after each spray. Pest control and fruit damage were compared to a standard spray program and a control plot in a different pear block located about 300 m from the S 71639 treated plots. The standard program consisted of the following sprays: 1) 15 May, Guthion 35 WP 12 oz; Agri-Mek 0.15 E 5 oz and superior type oil 1 qt/100 gal. 2) 5 Jun, Guthion 35 WP 12 oz/100 gal. 3) 9 Jul, Mitac 50 WP 12 oz/ 100 gal. 4) 19 Jul, Guthion 35 WP 12 oz plus Mitac 50 WP 12 oz/100 gal.

Insegar Rate Study, 1990

Abstract Mature bearing 'Anjou' trees were sprayed with aircarrier equipment applying 400 gal/acre for control of pear pests. Three rates of Insegar were compared to a standard program including a 15 May application of Guthion 35% WP 3 lb, Agri-Mek . 15 E 20 oz and oil 1 gal/ acre followed by a 19 Jun application of Guthion 35% WP 3 lb/acre. Insegar was applied 4 times during the season beginning at first egg lay of codling moth as determined by DD accumulation and again 21 d later for first generation then 2 second brood sprays timed the same way. Application dates and corresponding DD post biofix were as follows: 23 Apr, 74; 15 May, 231; 19 Jun, 586 and 9 Jul, 993. Plots consisted of 3 replicates of 30-40 trees in rectangles. Treatments were evaluated for control of PP and phytophagous mite species by counts made at 2-wk intervals. Adults PP were counted from a 25-beating-tray sample per replication. PP nymphs and phytophagous mites were counted from a 50-leaf sample per replicate. Leaf samples consisted of the proximal leaf, distal leaf and 3 leaves from the middle of 10 terminal shoots. Leaves were brushed and resulting slides were examined under magnification. Pest damage was rated according to U.S. grade standards for fresh market pears on 2 samples of 25 mature fruits per replication. Factors of fruit quality including firmness, soluble solids and size were evaluated from 2 10-fruit samples per replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicity after each spray.

Soft Pesticide Test, 1988

Abstract ‘Bartlett’ and ‘d’Anjou’ pears were sprayed with handguns operating at 600 psi to compare seasonal programs of soft pesticides for control of insect and mite pests of pear and for survival of beneficial arthropods. Plots consisted of 3 30-tree replicates in 3-row blocks. An untreated control was also included in the randomized block design. PP adults, PP predators, and the parasite Trechnites insidiosus densities were monitored by limb taps. PP nymphs were counted on 50-leaf samples/replication. Samples for first-generation nymphs were collected from fruiting spurs, whereas those for second and subsequent generations were collected from growing shoots. The proximal leaf, distal leaf, and 3 leaves from the middle were picked from each of 10 shoots. Leaves were processed with a leaf-brushing machine, and PP nymphs and mites were counted on 20% of the resulting slides with a binocular dissecting microscope. Pest damage to fruit was determined by examining 250 pears/replication at harvest. Fruit firmness, size, and soluble solids content were compared on 2 10-fruit samples/replication.

Insecticide Evaluations, 1988

Abstract Mature pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 single-tree replicates in a randomized block design. Treatments were applied 3 or 4 times depending on materials and schedules tested. Treatments were evaluated for PP and mite control by counts made at 2-wk intervals. Adult PP were counted from a 5-beating-tray sample/replication. PP nymphs and phytophagous mites were counted from a 50-leaf sample/replication. Leaf samples consisted of the proximal leaf, distal leaf, and 3 leaves from the middle of each of 10 terminal shoots. Leaves were brushed and slides were examined with a binocular dissecting microscope. PP russet was rated according to U.S. grade standards for fresh market ‘Bartlett’ pears on 2 samples of 25 mature fruits/replication. Factors of fruit quality, including firmness, soluble solids, and size, were evaluated from 2 10-fruit samples/replicate at normal harvest maturity. Fruit and foliage were examined for phytotoxicitv after each treatment.