Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) is a polyphagous parasitoid known to have an extremely wide host range, attacking larvae from at least 11 lepidopteran families. It was first detected in New Zealand in 1996 and spread rapidly, raising concerns that it may disrupt an integrated pest management program for Helicoverpa armigera (Hubner) that relied on two introduced larval parasitoids: Cotesia kazak and Microplitis croceipes. A series of laboratory experiments was undertaken to assess larval competition among these three parasitoid species. H. armigera larvae were exposed to the three parasitoid species in pairwise combinations and the subsequent formation of parasitoid cocoons and emergence of adults were recorded. Separate assays were run with 0, 24 and 48 h time intervals between ovipositions by each wasp species. The results showed that C kazak prevailed over M. pulchricornis and M. croceipes in all experimental combinations and time intervals, accounting for 79-100% of parasitoid cocoons, and that M. pulchricornis was similarly dominant over M. croceipes. The observed dominance of C kazak in processing tomato crops in New Zealand may be partly explained by the competitive advantage of its larvae, combined with a reportedly faster development rate. However, the nature of the competitive relationship between these species may well be modified by extrinsic factors in the field. In particular, M. pulchricornis may gain an advantage in more diverse cropping systems where it may exploit alternative hosts that are not suitable for the other species. (C) 2015 Elsevier Inc. All rights reserved.

The introduction of the eleven-spotted ladybird Coccinella undecimpunctata to New Zealand in 1874 has been widely quoted as the first importation of an insect for biological control in New Zealand and one of the first anywhere. However, searches of historical records show no evidence that such an introduction was made or attempted. Instead, there is clear evidence that the presently accepted record arose by a process of cumulative misreporting. An account of discussions in the Entomological Society of London in December 1873 about possible introductions of various beneficial insects to New Zealand was misreported by the American entomologist C. V. Riley, and several subsequent authors restated his version with further modifications and additions. This created the record of the introduction of C. undecimpunctata to New Zealand in 1874 that has been accepted and repeated ever since.

Natural populations of Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), also known as tomato/potato psyllid, were marked in potato [Solanum tuberosum L. (Solanaceae)] crops using Bacillus thuringiensis Berliner (Bt) to investigate the impact of dispersal on crop infestation and management of potential insecticide resistance in New Zealand. The technique was adapted from previous studies that used conventional spray applications of Bt to mark Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), and identified marked individuals with selective microbiological assays and identification of characteristic crystal inclusions. Initially, marking rates of B.cockerelli were improved by using ultra-low volume applications of undiluted Bt, but this result was not consistent. Several other pests and natural enemies were also marked. In mark-capture studies, marked B.cockerelli were captured over 3days on yellow sticky traps in small trap plots of potatoes at 60, 120, 180, 250, and 350m from the sprayed crop. Bactericera cockerelli flight activity occurred throughout daylight hours with evidence of bimodal diurnal peaks. Significantly greater numbers of B.cockerelli were captured in downwind traps. The combined dispersal curve derived from two mark-capture experiments estimated a mean dispersal distance for B.cockerelli of 100m in 3days and indicated that 10% of the population dispersed further than ca. 250m. Over the period of a growing season, this level of dispersal suggests that B.cockerelli can disperse throughout a vegetable-growing region, with implications for crop infestation and management of potential insecticide resistance.

Four species of Aphidius (Hymenoptera: Braconidae) were deliberately established in New Zealand in the period 1977-1994 for the biological control of pest aphids. Biological control practice and its regulation evolved over this period, so that whereas the evidence required for the 1977 introductions was based on literature records, by 1994 additional experimental or observational information was required. This paper describes the use of no-choice and choice tests conducted in 1996 and 1997 to retrospectively evaluate parasitoid host ranges and it considers if this information would alter the original regulatory decisions. The test species included several native aphids that were unknown at the time of the original parasitoid introductions. Consistent with literature records, the experiments confirmed that Aphidius eadyi Stary, Gonzalez and Hall was specific to its target host, and Aphidius sonchi Marshall was largely specific. Aphidius ervi Haliday and Aphidius rhopalosiphi De Stephani-Perez parasitized several test aphid species including cosmopolitan pest species already recorded in the literature, and some native test species. The patterns of mummification of individual test aphids varied greatly. Test aphids in the subfamilies Saltusaphidinae, Calaphidinae and Neophyllaphidinae appeared not to be at risk at all. The native Aphidini species Paradoxaphis plagianthi Eastop appeared to be more susceptible to attack by both A. ervi and A. rhopalosiphi than were P. aristoteliae Sunde or Aphis spp., suggesting that further investigations of P. plagianthi would be a priority if the introduction of these parasitoids were reconsidered now. Because P. plagianthi was not known when A. ervi and A. rhopalosiphi were introduced, prediction of their subsequent host range was limited by knowledge of the aphid fauna at that time. Therefore, reassessments of any decisions to release particular parasitoids would not be altered significantly by tests using knowledge available at the time of their introduction. However, if introduction of these parasitoids were to be considered today there would need to be a greater emphasis on determining their impact on (the recently documented) native aphid species. (C) 2013 Elsevier Inc. All rights reserved.

This review identifies factors that influence the development of integrated pest management (IPM) programmes and contribute to reducing risks from pesticide use. It examines how these factors may alter decisions concerning pesticide use as well as influence the choice of pesticide. The review focuses on IPM programmes in New Zealand in processing tomatoes, sweetcorn, vegetable brassicas, and potatoes, and compares these programmes with IPM in pipfruit. Factors examined include regulatory issues, markets and consumers, environment and sustainability, industry associations, the plant protection industry, growers, economic factors, science and technology, and implementation. Although requirements for export markets have been a key factor driving IPM in pipfruit, this has not been the situation in most vegetable crops, but this may change as quality standards become more important across all horticultural sectors. Sustainability problems, recognised as increased reliance on pesticides, lack of natural controls, and pesticide resistance, have contributed to crisis responses but have also helped to promote industry support of IPM programmes. Underpinning science, cohesive industry associations and the availability of selective pesticides were key requirements for IPM development, but the continuation and improvement of IPM in specific crops relies on ongoing, planned extension services.

The seasonality of Bactericera cockerelli, potato/tomato psyllid (PTP), a recently arrived pest of potatoes (Solanum tuberosum) and other Solanum spp., was investigated in South Auckland, New Zealand. Yellow sticky traps showed that adult PTP activity began in October mainly in volunteer potatoes and remained below c. 2/trap per week until mid December. Over this period, plant sampling was less sensitive than sticky traps. Potato crops harvested before c. 20 December showed satisfactory yield and quality. Trap catches in potatoes increased in late December and exceeded 100/trap per week in February in 2008 and 2009. The presence of nymphs in plant samples was positively correlated with these increases and associated with unacceptable levels of “zebra chip” disease and the presence of Liberibacter. Late planting of crops delayed the build up of PTP populations by c. 1 month, but nymphal populations still exceeded 1/leaf and damaged late crops. Yellow sticky traps provided an indication of when damaging plant infestations may occur, but further development of sampling techniques is required to derive damage thresholds.

Fungicide use in processing (field) tomatoes from 1995 to 2009 on the East Coast of the North Island of New Zealand has been documented using data extracted from growers' annual spray diary records. During this period, 26 different fungicidessome of which are also used as bactericideswere used by growers to control a range of plant diseases. The number of fungicide applications to each crop ranged from 10 to 28, with fewer applications in very dry seasons. Inorganic copper (mainly copper hydroxide), applied to control both bacterial and fungal diseases, was the most commonly used material, followed by chemicals in the dithiocarbamate, chloro-nitrile and pyridinamine groups. These four multi-site protective' fungicide groups accounted for 90% of all disease-control products used during the 15-year period. Site-specific fungicides (e.g. benzimidazoles, phenylamides, dicarboximides, dimethomorph and strobilurins) were used much less frequently. The exclusive use of fungicides at risk from fungicide resistance development (most commonly the site-specific fungicides) was generally avoided and therefore overall risk of the development of fungicide resistance in processing tomatoes in Hawke's Bay is believed to be low. This study demonstrated that the number of fungicide applications per crop has increased about two-fold since 1995 while, during the same period, insecticide applications decreased.

A new mark-capture technique involving field applications of Bacillus thuringiensis Berliner (Bt) to study the dispersal of potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), was investigated as a tool to improve information on the potential impact of insect pest dispersal on crop infestation and insecticide resistance. The acquisition and persistence of Bt on moths were characterized and potential contamination of moths from naturally occurring Bts was examined. This mark-capture technique was developed to mark larger numbers of moths than had been previously achieved with laboratory marking using fluorescent dyes in mark-release-recapture experiments. Applications of commercial preparations of Bt to 0.3 and 1.0 ha potato fields were estimated to have marked ca. 50 000 moths in each experiment. Pheromone trap catches of potato tuber moths in the Bt-sprayed fields and in potato fields at distances of ca. 80, 200, 350, and 750 m were assayed for the Bt marker using selective microbiological media and identification of characteristic Bt crystal inclusions. Marking rates of moths were 78-100% in the sprayed fields and, compared with our previous mark-release-recapture studies, marking at ca. 200 m was increased by 15-18-fold to > 3.0 moths per trap. This capture rate allowed the calculation of a dispersal curve that improved the reliability of estimates of movement at farm-scale distances. These estimates indicated that 10% of the population dispersed to 240 m in 3 days, and suggested that moths can potentially disperse throughout a typical potato-growing area in one growing season. This level of dispersal has implications for the spread and management of potato tuber moth populations, especially if insecticide resistance is present.

Soybean looper Thysanoplusia orichalcea (Plusiinae: Noctuidae) moths were first intercepted in New Zealand in 1984 by light trapping that was being used as a surveillance tool for new lepidopteran pests; in particular, noctuid species from Australia. This prompted studies on larval infestations to separate the impact of T. orichalcea caterpillars from that of the closely related indigenous green looper, Chrysodeixis eriosoma. Subsequent studies described here show that the establishment phase took place over c. 3 years and that, rather than replacing the resident green looper, soybean looper added to the population density of plusiine caterpillars in several field crops, especially lucerne, parsley, soybeans, brassicas, and lettuce. The increases in larval populations caused by T. orichalcea in soybeans were documented from 1980 to 1989, with total plusiine populations reaching c. 46/m of row compared with c. 10/m of row for C. eriosoma. Light trap catches of moths confirmed the increasing abundance of T. orichalcea. By 1990 it represented 87% of the plusiine moths trapped at Pukekohe. This case history supports the use of light traps as a surveillance tool to provide biosecurity warnings and to initiate establishment and impact surveys for incursions of new noctuid pests.

Spodoptera litura (F.) and Helicoverpa armigera (Hübner) are potential non-target pests in Bacillus thuringiensis (Bt)-transformed potato and brassica crops that are currently being investigated as candidates for field release in New Zealand. The comparative susceptibility of these pests and two of their larval parasitoids to Bt toxins was examined using diets amended with commercial preparations of Bt sprays and Cry1Ac toxin preparations. Using concentrations that allowed survival of some of the parasitoids and their hosts, development and survival characteristics were compared at two rates of Dipel 2X, six rates of Cry1Ac, and two reduced-nutrition diets. For all these treatments, larval development of both parasitoids, Cotesia kazak (Telenga) and Meteorus pulchricornis (Wesmael), was delayed only when there was a significant impact on the host Lepidoptera. Survival of M. pulchricornis was unaffected even when the survival of S. litura larvae was mildly, but significantly, reduced. In H. armigera, Bt diets that caused severely reduced survival of the host were accompanied by reductions in survival of M. pulchricornis. Similar or increased levels of survival of C. kazak were noted in H. armigera that were fed less toxic Bt-amended diets. Poor survival of parasitoids on reduced-nutrition diets suggested that reduced nutrition had a comparatively greater effect on parasitoid survival than Cry1Ac toxins. Overall, when Bt was ingested at concentrations that had minor effects on development or survival of host larvae, there was no impact on either parasitoid species. Further experiments with specific Bt cultivars proposed for release are required to confirm that in any surviving larvae, the impacts of Bt on these parasitoids are likely to be fewer than the impacts on their non-target hosts.

Two parasitoids,Cotesia kazak (Telenga) and Microplitis croceipes (Cresson) have been successfully introduced into New Zealand to improve control of Helicoverpa armigera (Hübner), tomato fruitworm. C. kazak has spread throughout the North Island, but M. croceipes is restricted largely to its release areas in crops in the Gisborne and Hawke’s Bay regions in the East Coast of the North Island and in pine plantations in the central North Island. Rates of mortality of H. armigera from parasitism were studied in processing tomato crops where these parasitoids are a key component of an integrated pest management programme, and in sweet corn, lucerne and soybeans. C. kazak was the dominant parasitoid in tomatoes and soybeans. It emerged from small H. armigera larvae and usually killed the host before it caused major damage to fruit. M. croceipes emerged from larger host larvae than C. kazak. Death rates from parasitism of H. armigera larvae in tomatoes increased from less than 1% caused by native parasitoids prior to parasitoid introductions, to 25–45% in 1988 and 70–80% in 1996 following the establishment of both introduced parasitoids. M. croceipes was the most common parasitoid in lucerne and total mortality from all parasitoids was similar to that in tomatoes. Low rates of parasitism by C. kazak in sweet corn were attributed to the reduced penetration of the adult parasitoid into sweet corn fields and to the protection afforded by sweet corn when H. armigera larvae burrowed into corn cobs. The implementation of an IPM programme based partly on the effectiveness of these parasitoids has contributed to a decrease in insecticide applications to processing tomatoes.

Abstract Laboratory studies confirmed that commercial formulations of Bacillus thuringiensis (Bt) could be used to mark potato tuber moths, Phthorimaea operculella. Moths were successfully marked by direct application or through indirect acquisition by contact with marked surfaces such as a leaf or a Petri dish. Marked moths were identified by the distinctive crystalline morphology of different subspecies of Bt, allowing the separation of individual moths marked with either Btk (kurstaki) or Bti (israelensis). A simple microbiological method for processing the trapped moths before definitive, microscopic identification of the subspecies is described. Field marking was verified by capturing light brown apple moths, Epiphyas postvittana, from areas that had been subjected to large‐scale spraying of Btk for control of an exotic pest species. Btk was also detected in moths from isolated traps at c. 1 km from the treated area, but not in moths from traps at greater distances. These results indicate that Bt preparations could be used to mark naturally occurring populations as well as laboratory‐reared individuals to study their dispersal.

Mating of potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), was investigated in relation to the dispersal of males in laboratory and field trials. The effect of stimulating the flight of males to light sources in a large cage on their mating ability was estimated for three age groups, and compared with similar estimates for confined moths. Although the mating of males declined with ages of up to 15 days, simulated dispersal had no effect on subsequent mating when the males were paired with virgin females. The dispersal of male moths was also categorised by the initial flight activity of untethered moths to a light source. Scores for poor, moderate, and good flight provided a repeatable measure of initial male flight activity, but the degree of activity was not related to their subsequent mating ability. In the field, virgin female potato tuber moths were tethered at various distances from the edge of isolated potato crops and then dissected to determine their mating status. Female mating frequency averaged 75% at the crop margin, remained above 50% up to 200 m, and then declined to 19% at 360 m from the margin. Derivation of the mating probability for an individual male potato tuber moth confirmed earlier work by other researchers that has indicated a tendency for dispersal prior to mating, and that males retain their ability to mate as they disperse from a crop. The influence of dispersal and mating on gene flow between crops, and its potential effects on refuge size required to minimise the development of resistance to Bt transgenic potato crops was examined.

The parasitold, Cotesia plutellae, is used as a biological control agent for diamondback moth, Plutella xylostella, in many countries and has been evaluated as a candidate for release in New Zealand. C. plutellae was originally released in Australia in 195 1, but is rarely found. A glasshouse host specificity trial was conducted in Australia to assess whether C. plutellae would parasitise Nyctemera amica, magpie moth, on the noxious weed ragwort (Senecio jacob ae a L.) in the presence of P. xylostella on cabbage. Although P. xylostella was expected to be the preferred host of C. plutellae, a greater proportion of the N. arnica larvae was parasitised. It is likely, therefore, that C. plutellae Would parasitise N. amica on ragwort in the vicinity of Brassica plants in the field. The closely related moth, Nyctemera annulata (Boisduval), is valued as a native species in New Zealand and significant parasitism of this insect would not be acceptable. The proposal to release C. plutellae will not be pursued until further information on host specificity is obtained.

In New Zealand, increasing levels of resistance in diamondback moth (DBM) to recommended synthetic pyrethroid and organophosphate insecticides were monitored for Five years in vegetable Brassica crops until in 1997 they were associated with control failures in three regions. Subsequently, Crop & Food Research initiated a two-year IPM implementation programme with financial assistance from government and industry, including agrochemical companies. The IPM programme emphasizes the use of a reduced spray programme developed in the early 1990s based on a crop scouting system using presence/absence per plant of the major pests and a proven action threshold for cabbage. Further research has reconfirmed this cabbage action threshold, and broccoli and cauliflower action thresholds have been developed. The implementation phase involved training scouts and crop managers in insect identification and crop scouting techniques, and incorporated an accreditation system for trainees and a crop management recording system to document insecticide use in the IPM crops. Demonstration sites in three of the main Brassica growing regions were used for grower field days and to compare IPM practices with conventional pest management. Levels of resistance in DBM to the commonly used groups of insecticides were monitored and resistance levels were compared within a region as well as between regions. The IPM programme also recommends an insecticide resistance management rotation strategy with different chemical groups assigned to two different seasonal windows as well as the preferential use of selective insecticides to preserve natural enemies. An independent survey in November 2001 reported that 80% of growers in the main Brassica-growing region were using IPM and 96% were using crop scouting. Crop management records from IPM crops show an average saving of at least 50% in insecticide use compared with conventional crops.

A New Zealand guide for pest, disease and weed management in organic arable andvegetable crops was developed. This guide is a resource for current organic growers andtheir consultants, as well as those contemplating converting to organics. It includesinformation collected from a wide range of sources within New Zealand and overseas.The guide has three parts: (I) a general section on the principles of soil, pest and diseaseand weed management in organic systems, (II) an arable section covering barley, borage,clover seed, grass seed, lentils, linseed, maize and wheat, and (III) a vegetable sectioncovering asparagus, brassicas, capsicum, carrot, onion, peas, potato, squash and tomato.For each crop there is a summary of the main pests, diseases and weeds to identify thepotential risks to organic growing. The options for preventing or managing these risksthat are available to organic growers given the cropping operations and control alternativesavailable to them are then described. This guide aims to fill the current gap between“introductory” and “anecdotal” organic publications with comprehensive documentationof growing operations that have been used successfully in specific crops for organicpest, disease and weed management.

The efficacy of insecticides for the control of Nezara viridula (L.) (Hemiptera: Pentatomidae), the green vegetable bug, was tested in laboratory and field trials. Bioassays of 11 insecticides against field-collected adults were used to select two insecticides for a field experiment conducted in a process sweet corn crop, Zea mays (L.) (cv. Punch), near Tolaga Bay on the east coast of the North Island, New Zealand. Lambda-cyhalothrin (as 200 ml Karate(R)/100 litres water ha(-1)) and methamidophos (as 1 litre Tamaron(TM)/100 litres water ha(-1)) were tested against a water control. Both insecticides demonstrated efficacy, with respective mortality rates of 87 and 83% compared with 2% in the control. Green vegetable bug flew into the experimental crop in large numbers over 48 h before the start of the trial. Damage thresholds were exceeded in two of the three control plots within 7 days of the green vegetable bug first invading the crop, leaving only a very small 'window' for insecticide application. Success or otherwise of these insecticides is therefore likely to be dependent on the timing of application as well as on the efficacy of the products themselves.

Movement of potato tuberworm, Phthorimaea operculella (Zeller), and diamondback moth, Plutella xylostella (L.), was examined indirectly by estimating their distribution, and directly by using mark-recapture techniques. Trapping techniques including trap tubers and trap plants were used to assess the distance that potato tuberworm moved from infested crops. These experiments suggested that a low proportion of moths foraged beyond 100-250 m to infest tubers or plants. Light traps indicated that the number of moths moving out from crops diminished over a 40-m distance. Dispersing moths penetrated 30 m into new crops to infest the foliage. Direct movement of potato tuberworm and diamondback moth between crops was estimated using mark-recapture experiments. Fluorescent dusts were more effective than felt pen for marking, and moths were recaptured with sweep-nets followed 1 d later by pheromone trapping. From sweep-net collections of potato tuberworm, a mean of approximate to17% of moths was shown to move between crops. Only 1.2% of diamondback moth was recaptured by sweep netting outside the release area and very few moths were caught in pheromone traps. These results, together with the literature, suggest that sufficient potato tuberworm would forage between adjacent treated and untreated crops to minimize the development of insecticide resistance. The use of refuges to conserve susceptible pest populations is recommended for managing resistance that may arise from any future use of Bt-transgenic potatoes or Brassica spp. in New Zealand. Refuges that are intended to dilute potential resistance of potato tuberworm to transgenic crops should be placed close to transgenic potato crops.

Cotesia rubecula (Marshall) was first released in New Zealand for control of Pieris rapae (L.) in December 1993. It has since been released in nine regions and is established in eight of these, from Northland to Southland (35degrees 15' S to 46degrees 10' S). Natural geographic spread of C. rubecula has averaged approximate to2 km/yr in the Pukekohe area in South Auckland. Death rates due to parasitism ranged from 48 to 97% of host larvae at selected study sites, but were lower at most commercial sites. Three paired comparisons of sites with and without C. rubecula showed that the parasitoid reduced the survival of P. rapae larvae and limited the density of fifth instars. Although C. rubecula reduced parasitism by Cotesia glomerata (L.) in sites where they were both present, total parasitism of P. rapae was increased at these sites. Some hyperparasitism of C. rubecula by Tetrastichus galactopus was observed, but it does not appear to be limiting establishment of C. rubecula.

Field sampling methods and economic thresholds were developed to provide management recommendations for Helicoverpa armigera (Hübner) on processing tomatoes, based on a commercially acceptable damage level of 5% fruit damage. Population estimates from destructive sampling and a rapid 1-min plant scouting method were related to fruit damage, and a nominal economic threshold of one larva per plant was derived. The economic threshold was confirmed in a designed trial where it resulted in acceptable levels of fruit damage. The 1-min scouting method and economic threshold was validated in 17 commercial crops in the Gisborne, Poverty Bay region of New Zealand. Scouting in these fields was based on 10 plants in each of four quadrants proportionally representing the topography of each field. In unsprayed areas, egg and larval populations were usually below the economic threshold in early-planted crops but often exceeded thresholds in late-planted crops. In commercial demonstration trials where standard calendar spraying practice was compared with no spraying, calendar-based applications maintained fruit damage below 3.4%, but insecticide was applied unnecessarily to more than half the crops. Larval populations were a significant predictor of damage in these commercial crops. In 12 implementation trials, where spraying recommendations were based on the 1-min scouting threshold of one larva per plant, the worst fruit damage observed was 2.3%. The definition of an economic threshold, scouting methods, and establishment of parasitoids have reduced spray applications and contributed to the implementation of an integrated pest management program for processing tomatoes in New Zealand.