Zealand Apple Orchards Research Articles

Invertebrate biodiversity in apple orchards: agrichemical sprays as explanatory variables for inter‐orchard community differences

Abstract Invertebrates are important providers of ecosystem services to orchards and the orchards may benefit where there is greater biodiversity. Previous research has shown that apple orchards using organic or integrated pest management support different invertebrate communities, as can different orchards within the same management system. In the present study, we examined the potential for agrichemical usage to explain inter‐orchard invertebrate community differences in 10 New Zealand apple orchards under integrated pest management. Multiple regression models were used to examine relationships between spray diary data and invertebrates collected by branch tapping, pitfall and sticky traps in 2011/2012. Insecticides, fungicides, plant growth regulators and fertilizers were used as explanatory variables in these models and the most parsimonious models were identified. Plant growth regulators were significant in most of the models for inter‐orchard variability in total invertebrate diversity. Insecticides featured strongly in models explaining pest assemblages, although not so strongly for models for their natural enemies. Fungicide and fertilizer use featured in models explaining communities of decomposers and fungivores. The results generated several hypotheses about the impacts of specific agrichemicals on invertebrate biodiversity, which, if tested, could establish the feasibility of customizing spray schedules to meet both biodiversity and production goals.

Comparison of invertebrate biodiversity in New Zealand apple orchards using integrated pest management, with or without codling moth mating disruption, or organic pest management

Abstract On-farm biodiversity is increasingly perceived as an indicator of sustainable practices. However, in-depth examinations of the influence of management on the components of this diversity (specific taxa, feeding guilds, pests, ecosystem service providers, native taxa, and so on) are still lacking for many crops and growing regions. To compare the diversity of invertebrates in commercial apple orchards using three different pest management systems (Integrated Fruit Production with or without codling moth mating disruption and certified organic), we collected taxa from five of each type of orchard in Hawke’s Bay, New Zealand. We used pitfall traps, branch tapping and sticky traps to collect 210,829 specimens, representing 764 taxa, during two sampling sessions: December 2011 and February/March 2012. Groundcover plant communities in the alleys between tree rows were not detectably different among the three orchard types. Multivariate analysis showed that the composition of invertebrate communities sampled from organic orchards differed significantly from those in orchards using the two different integrated pest management systems and that the use of codling moth disruption in the integrated systems had no discernible impact on invertebrate biodiversity in those orchards. Sub-group analysis revealed some differences between integrated and organic orchards for herbivores, predators and parasitoids, but not omnivores, detritivores and fungivores. Native or endemic species comprised 40% of taxa in all three orchard types, and there were no detectable differences in the composition of these assemblages among orchards. Assemblages of apple pests in organic orchards differed significantly from those in the other orchard types, but this effect was lost if Edwardsiana froggatti, which was abundant in organic orchards, was omitted from the analysis. All orchard types had similar assemblages of key natural enemies, suggesting that current integrated pest management systems employed on apple orchards in New Zealand have similar impacts to organic systems in this respect.

Teaching Future Crop Protection Practitioners through the Use of On-line Cases: Practicing IPM Spray Decisions in New Zealand Apple Orchards

Purpose: There are many complexities to be considered when selecting tactical control options in crops grown under an Integrated Pest Management (IPM) regime. Students being trained in IPM are made aware of this complexity but do not always get the chance to experience IPM decision-making first-hand. This case study describes a web-based assessment and presents student feedback as to its value.Design/Methodology/Approach: Students are required to analyse the pest and disease status of and provide pesticide recommendations for an export apple orchard at four different times of the season. At each ‘virtual visit’ they are required to interpret monitoring data and make spray decisions. The students are provided with the same IPM information and guidelines commercial growers receive. Amongst other things, management history, non-target organisms, pesticide resistance risk, allowable residues, pesticide restrictions and pesticide compatibility must be considered. Student reflections (n = 57) from three years of use were assessed using grounded theory analysis and reported.Findings: Students found they gained an appreciation of the various factors that need to be considered for tactical IPM and that the exercise helped prepare them for this task ‘in real life’.Practical Implications: The assessment described can be used as a template for an online integrated case-based training strategy which provides the opportunity for real-life decision making in a safe environment.Originality/Value: The paper is original. It is hoped this case study will serve as a source of ideas and/or inspiration from those wishing to employ similar ‘active learning’ web-based exercises for agricultural education or extension training.

Optimising methods for collecting Hymenoptera, including parasitoids and Halictidae bees, in New Zealand apple orchards

We monitored four groups of Hymenoptera in organic apple orchards in New Zealand in order to assess different trapping methods. The factors assessed were trap type (pan traps vs. sticky traps), trap colour, preservative type and trap position within the orchard with regard to the shelterbelt.Yellow sticky traps were the most effective trap type overall for sampling the order Hymenoptera, and the two parasitoid species Anagrus sp. and Aphelinus mali (Haldeman). White pan traps were best for sampling native bees from the family Halictidae. Choice of preservative in the pan traps significantly affected the catch of Hymenoptera overall and Halictidae. Most Hymenoptera were more abundant within the orchards than at the shelterbelt, except the Halictidae, which were more abundant at the shelterbelt. The results support the notion that Hymenoptera surveys should be conducted using methods appropriated for targeted taxa, due to differences in their behavioural responses and ecological trends.

Resistance of <i>Venturia inaequalis</i> to quinone outside inhibitor (QoI) fungicides in New Zealand apple orchards

DNA sequencing and optimisation of allelespecific primers targeting the G143A mutation which confers resistance in Venturia inaequalis (apple black spot) to quinone outside inhibitor (QoI) fungicides was used to develop a resistance testing method for orchard surveys The method confirmed the resistance status of 15 V inaequalis isolates that were classified as sensitive or resistant to trifloxystrobin using a mycelial growth assay Disease caused by four isolates carrying the G143A mutation was not controlled by the QoI fungicide trifloxystrobin in an inoculated potted tree experiment In a survey of 41 apple orchards in Hawkes Bay Nelson Otago and Waikato during 201112 the G143A mutation occurred in 54 of 802 V inaequalis isolates and 59 of orchards had more than 50 of isolates with the mutation present The results indicate that orchards with a high G143A mutation frequency can be expected to experience loss of black spot control where QoI fungicides are used

Diversity of natural enemies in Central Otago, New Zealand apple orchards: a practical measure of sustainability in pest management?

The diversity of the arthropod fauna in apple orchards in Central Otago was recorded from 1994 to 1999 using beating trays, pitfall traps, and sticky traps and the data analysed by the Shannon–Wiener Index. Three different fruit production systems were compared, conventional (CFP), integrated (IFP), and biological (BFP), to determine whether total arthropod diversity and/or the diversity of natural enemies (predators and parasitoids) could be used to measure the sustainability of their pest management practices. The contribution of natural enemies to the diversity indices was also examined to determine if they reflected the key species essential for sustainable pest management. The diversity of natural enemies in beating trays was found to be the measure most sensitive to changes in pest management. The diversity of both the total arthropod fauna and natural enemies was much lower under CFP than under either IFP or BFP, due to the use of broad-spectrum pesticides. This practice made the CFP programme unsustainable and it is no longer used. During the transition from CFP to IFP, the diversity indices rose to become similar to that in the BFP programme by the third season. The introduction of frequent applications of fungicides in BFP, including lime sulphur, appeared to reduce total arthropod and natural enemy diversity. Falls in the diversity indices for natural enemies were shown to reflect reduced numbers, range, and evenness of natural enemies but not necessarily the key species known to be critical for sustainable pest management. It is proposed that a Shannon–Wiener Index for natural enemies in beating trays of 0.2 or less in summer is strongly indicative of unsustainable pest management in Otago apple orchards. On the other hand, indices of 0.3–0.8, as found under IFP and BFP, do not give unequivocal or quantitative indications of the sustainability of pest management. A suite of other measures of sustainability are more useful, notably combining lower pesticide use, reduced pest damage and presence at harvest, the greater roles of key natural enemies, more effective plant resistance to pests and diseases, and higher profitability.

Toxicity of pesticides to <i>Aphelinus mali</i> the parasitoid of woolly apple aphid

The parasitoid Aphelinus mali controls woolly apple aphid (WAA; Eriosoma lanigerum) in New Zealand apple orchards The effects of seven pesticides on A mali exposed to residues on filter paper were assessed in a laboratory bioassay immediately postapplication Spinosad at label rate was moderately to highly toxic but other compounds and lower rates of spinosad had no detrimental effects on A mali Another bioassay incorporating field application and exposure to aged residues on leaves determined the toxicity of carbaryl diazinon indoxacarb and lime sulphur Carbaryl had the greatest residual toxicity to A mali on harvested leaves causing 85 mortality 21 days after application declining to 40 by 28 days In contrast diazinon initially caused high mortality but residues were not toxic 15 days after application while indoxyacarb and lime sulphur were not toxic Minimising the use of pesticides toxic to A mali should benefit the sustainable management of WAA in apple orchards

Efficacy of the pear ester as a monitoring tool for codling moth Cydia pomonella (Lepidoptera: Tortricidae) in New Zealand apple orchards

The behavioural response of both sexes of codling moth, Cydia pomonella to the pear-derived kairomone (ethyl (2E,4Z)-2,4-decadienoate), codling moth sex pheromone (E,E-8,10-dodecadien-1-ol), and sex pheromone combined with the pear derived kairomone loaded into red rubber septum were investigated in trapping experiments in New Zealand apple orchards. A range of 0.01-10.0 mg of pheromone loading in rubber septum dispensers was tested and the highest catch of males was in traps baited with 1.0 mg. No dose response in trap catch of males was seen in traps baited with different amounts of pear-derived kairomone (0.01-10.0 mg). The number of females caught was significantly affected by the amount of pear derived kairomone used to bait traps, with the highest catch obtained at 10 mg loading. The attractiveness of sex pheromone was not enhanced by the addition of the kairomone either when used in the same bait or in a separate bait. The mean number of males captured in traps was reduced by 44% when the pheromone and kairomone were combined at ratio of 1:1 (0.1 mg pheromone: 0.1 mg kairomone) in separate sources. Kairomone baited traps showed some potential for monitoring the flight activity of female C. pomonella in apple orchards in two locations (Canterbury and Hawke's Bay). However, the number of male moths caught was low as compared to the number of male moths caught in pheromone-baited traps, and therefore the sex pheromone should continue to be used for monitoring male activity.

Ecological impact of three pest management systems in New Zealand apple orchards

Three apple pest-management regimes are being compared for their ecological impacts, and their ability to ensure the economic production of high-quality apples. Species diversity, pest status and fruit quality are being evaluated under: (i) conventional, (ii) integrated, and (iii) biological fruit production systems. The conventional system follows current export orchard practices with broad-spectrum pesticides, and the integrated system uses a wider range of control methods, including minimal spray applications, preferably of selective pesticides. The biological system uses mating disruption for codling moth (at one site), Bacillus thuringiensis for leafrollers, copper/slaked lime for diseases, and matting or mulches for weed control. Conventional production results in few insects being present during the season and little damage at harvest, but increasing insecticide resistance problems and changing market requirements put the sustainability of this system in doubt. In the integrated system, excellent control of Lepidoptera has been achieved using tebufenozide, with little effect on natural enemies. Further development of the system is needed, but the economics appear favourable for producing export-quality fruit in future. In the biological system, the lack of effective controls for key quarantine pests limits economic sustainability and largely restricts production to the local market. The future of this system for export production depends on innovative technology to overcome these problems.

The tree-row-volume spraying system and its potential use in New Zealand

Tree canopy sizes and training systems can vary widely on modern apple orchards, but most growers do not have the information required to determine appropriate spray volumes and chemical rates for different canopies. Chemical rates and volumes currently used in the majority of New Zealand apple orchards are derived from an arbitrary standard application rate of 2,000 litres/ha. The Tree-Row-Volume (TRV) system for describing spray volume requirements on different canopies has been tested and widely adopted in America, but the American system appears not to work with New Zealand canopies and has not been adopted here. Development and validation of a modified TRV estimation system for use on New Zealand apples are described in this paper and potential benefits of TRV spraying are discussed.

Incidence of bacteria inhibitory to Erwinia amylovora from blossoms in New Zealand apple orchards

Populations of total bacteria and Erwinia herbicola were monitored on apple blossom in selected orchards at two different geographical regions in New Zealand (Canterbury and Hawke's Bay). In all four orchards surveyed E. herbicola populations remained negligible (less than 50cfu/blossom) throughout flowering, increasing rapidly at petal drop to reach levels of 1 × 103 cfu/blossom (Hawke's Bay) to 1 × 105 cfu/blossom (Canterbury). Total bacterial populations increased 100‐fold at petal drop in both locations. Pseudomonas populations were predominant in Canterbury throughout all flowering stages and in Hawkes Bay after early flowering. When screened for inhibitory activity to E. amylovora, 26% of all isolates from Canterbury showed some inhibition in vitro, but none of the isolates from Hawke's Bay showed inhibition of E. amylovora in vitro. Two Canterbury isolates with strong in vitro inhibitory activity also inhibited E. amylovora in immature pear fruit. One isolate was identified as E. herbicola and one isolate as Pseudomonas fluorescens.

Pest and disease management in Hawke's Bay, New Zealand apple orchards: Results of an “advice‐givers” survey

Abstract Twenty‐seven Hawke's Bay, New Zealand apple (Malus domestica Borkh.) pest and disease control “advisers” including horticultural merchant and New Zealand Apple and Pear Marketing Board (NZAPMB) field representatives, private consultants, and apple plant protection scientists (The Horticulture and Food Research Institute of New Zealand Ltd (HortResearch)) were interviewed over the 1993/94 growing season to determine their role in growers’ pest and disease spray decision‐making. Horticultural merchant representatives considered themselves to be the main spray decision‐maker for 40% of growers. In the opinion of the latter, 50% of growers expected the horticultural merchant representative to know more about the problems in the orchard than they did themselves. Plant protection scientists and (increasingly) NZAPMB representatives play an important role in strategic pest and disease advice to the industry. Growers are very well serviced in the Hawke’ s Bay region which has led to an expectation of “free” advice regarding pest and disease management. Spray recommendations from merchant representatives and consultants are generally risk‐free and prescriptive, with a large safety margin applied for unskilled growers. Introducing more complex spray‐saving techniques, or taking full advantage of those that already exist, will require many growers either to upskill themselves, or employ consultants to manage their orchards. NZAPMB/HortResearch seminars and bulletins along with an on‐line advisory service (e.g., Orchard 2000) could play a useful role in educating growers and providing more complex advice. Basic pest and disease identification and biology, together with a knowledge of pesticides are regarded as being essential to manage pests and diseases successfully. Nutritional problems and resistance development are two areas where more knowledge is required.

Assessment of azinphos-methyl resistance in apple leafcurling midge from New Zealand apple orchards

Assessment of azinphos-methyl resistance in apple leafcurling midge from New Zealand apple orchards

Incidence of <i>Erwinia herbicola</i> in New Zealand apple orchards: implications for biological control

Incidence of <i>Erwinia herbicola</i> in New Zealand apple orchards: implications for biological control

Simulation model of the European red mite andTyphlodromus pyri in New Zealand apple orchards

A deterministic model of the European red mitePanonychus ulmi (Koch) and its predatorTyphlodromus pyri Scheuten is presented. The model is driven by daily maximum and minimum temperatures, and requires the per-leaf densities of both mites in spring to start each simulation. It was successful at predicting the general change in mite populations, and the peak prey density, but deviations from field results occurred at low prey density. Simulations have suggested that the present miticide spray thresholds used in New Zealand are too conservative and have also provided further insight into integrated control ofP. ulmi.

A laboratory study on the predatory mite, Typhlodromus pyri (Acarina: Phytoseiidae). II The effect of temperature and prey consumption on the numerical reponse of adult females

SummaryThe numerical response of adult female T. pyri feeding on different levels of ERM larvae, and at a range of temperatures was examined. The duration of the pre‐oviposition period decreased as larval consumption increased, and the rate of oviposition was linearly related to the rate of consumption of larvae. Mathematical models were used to describe these relationships in terms of temperature and consumption of ERM larvae. The results were discussed in relation to the nature of the T. pyri/ERM interaction in New Zealand apple orchards.