Integrated Fruit Production in Canterbury (pest control)
Integrated Fruit Production (IFP) trials in Canterbury form part of a research programme to develop and test an IFP programme for apples in Hawke’s Bay, Nelson, Canterbury and Central Otago. Results from this research have been used to develop the ENZA IFP-P manual.
In this article, we present results from the pest control trials carried out in Canterbury over the past 2 years. The purpose of these trials has been :
Here we discuss the effects of the IFP programme on the different insect species in the orchard as well as comparing the levels of pest control achieved by IFP, conventional and organic programmes. Details of fungicides are included for completeness, but this information is separate from the pest control trials, (see Organic alternatives to black spot and powdery mildew sprays).
So far, the prospects for Integrated Fruit Production in Canterbury appear to be excellent with very few harvested fruit damaged by pests (see Tables 1 and 2 ).
The trials ...
At Lincoln University, the following trials have been set up over the past two years to compare different growing systems :
In addition, trial IFP programmes were run at three commercial properties in Canterbury.
The spray programme
The IFP programme in Canterbury is based on Mimic. A maximum of four applications of Mimic at monthly intervals should achieve adequate control of leafroller and codling moth in Canterbury. Earlier varieties (eg. Royal Gala) may only need three applications. Mimic is a more persistent pesticide than either azinphos-methyl or chorpyrifos so there is no need to over-spray.
The success of an IFP programme depends on populations of pest predators and parasites becoming established in the orchard. At this stage, a parasite, Aphelinus mali, appears to be controlling woolly apple aphid on the trial blocks. Populations of other predators and parasites should build-up provided organophosphates (eg. chlorpyrifos) are not used.
Please click here for further details of the spray programmes used on the IFP, BFP and OP blocks at Lincoln University. The IFP programme, in particular, is still being developed.
Pest monitoring
For details as to how the insects were monitored, see Pest monitoring in an IFP programme
Success of the programme
All the fruit harvested from the IFP blocks (including commercial and research blocks) had very low levels of insect damage to the fruit. In fact there was minimal difference in overall pest damage between the IFP and OP block which had received a full insecticide programme. The BFP fruit also had low levels of insect damage. However, this fruit was not as clean as that from the IFP or OP blocks due to high levels of black spot.
Table 1 shows the levels of damage from each of the three programmes at Lincoln University and Table 2 shows the overall levels of damage of fruit from the three commercial orchards managed under an IFP programme.
Table 1. An assessment of damage to fruit (1000 Fuji apples sampled) harvested from Lincoln University, from biological, integrated and conventionally managed blocks.
| Block | % Clean fruit1 | % Fruit damaged / infested | |||||
| insect & disease | insect | leafroller | black spot | codling moth | noctuid | European red mite | |
| BFP | 79 | 95 | 4.9 | 18.1 | 0.2 | 0.0 | 0.0 |
| IFP | 92 | 99 | 0.6 | 8.5 | 0.0 | 0.0 | 0.0 |
| OP | 95 | 98 | 1.2 | 3.0 | 0.0 | 0.5 | 0.1 |
1 assessment excludes colour, russet, size and physical damage | |||||||
Table 2. An assessment of damage to fruit (1000 each of Braeburn and Red Delicious apples per sample) on three orchards using Mimic and organophosphate based spray programmes.
| Grower | Cultivar | Treatment1 | % clean fruit 2 | % leafroller damage | % woolly apple aphid | % oystershell | |
| Mimic | OP | infestation | scale infestation | ||||
| A | Braeburn | 5 | 1 | 99.4 | 0.6 | 0.0 | 0.0 |
| B | Braeburn | 5 | 1 | 100 | 0.0 | 0.0 | 0.0 |
| B | Braeburn | 6 | 100 | 0.0 | 0.0 | 0.0 | |
| C | Braeburn | 2 | 1 | 99.6 | 0.3 | 0.0 | 0.1 |
| C | Red Del. | 2 | 1 | 99.5 | 0.3 | 0.2 | 0.0 |
|
1number of applications of post-bloom insecticides 2fruit clean of insect damage; excluding colour, russet, size, other damage etc. | |||||||
Control of individual pest species
Leafrollers
At Lincoln, adult leafrollers (the greenheaded leafroller , Planotortrix octo ; lightbrown apple moth , Epiphyas postvittana ; brownheaded leafroller , Ctenopseustis herana) as well as a larval parasite (Dolichogenidea tasmanica) were caught in pheromone traps in all three blocks. The researchers also found live leafroller larvae, especially in the IFP block (22 live larvae) and BFP block (65 live larvae). The high numbers of leafroller larvae are partly due to poorly trained trees in the IFP and BFP blocks which resulted in poor spray coverage. However, over half of the leafroller larvae caught from the IFP block died after capture, probably due to delayed effects of Mimic.
Adult female and male of greenheaded leafroller
Despite these high populations of leafroller, the three Mimic post-bloom insecticides were able to keep leafroller damage to 0.6% in IFP fruit. On the BFP block the level of damage was higher. In a BFP programme, better spray coverage, as well as other biological forms of control, may be necessary.
Codling moth
Very little codling moth , damage was found on any of the trial orchards. A small amount of codling moth damage (0.2% fruit damage) was found in the BFP block at Lincoln, but the moths did not infest the adjoining IFP block.
Woolly apple aphid
This pest has caused little damage so far, but it could potentially pose a problem to IFP production in Canterbury. The parasite, A. mali, seems to have some control of woolly apple aphid. However, organophosphate sprays will wipe out A. mali. For example, a high level (11%) of the woolly apple aphid colonies were controlled by parasites in the spring, but after the first two organophosphate sprays, the level of parasitised colonies was reduced to zero.
Commercial orchards, which have used organophosphates in the past, may not have existing populations of A. mali so new populations need to be introduced into the orchard. We don’t know yet how long it will take for A. mali to become established to a level where it will provide effective control of woolly apple aphid.
Mites
European red mite , (ERM) and two spotted mite, (TSM) can be problem pests in Canterbury. However, only ERM was present on the monitored orchards during 1995/96. In the Lincoln trial, the predatory mite, Typhlodromus pyri, was able to maintain ERM below the economic threshold in the IFP and BFP blocks. In the OP block, however, ERM exceeded the economic threshold of 200 active stages/leaf in late January. As the level of ERM was borderline for control, no miticide was applied and only 0.1% of fruit was infested with mites at harvest.
Twospotted spider mite adult and egg
Apple leafcurling midge
Apple leafcurling midge , Apple leafcurling midge (ALCM) is still fairly rare in Canterbury, although the midge could become a problem under IFP conditions. Monitoring has revealed that there are three generations of ALCM in Canterbury.
In other districts, a foliar application of diazinon, applied in response to the first generation of ALCM eggs, provides the most effective control possible from a single insecticide application (IFP-P Manual threshold : > 20% shoots infested with ALCM eggs). However, in Canterbury the first generation coincides with flowering so no sprays can be applied. HortResearch researchers will test a post-flowering diazinon on the Canterbury trial blocks next season.
Froggatt’s apple leafhopper
Scientists have recorded two generations of Froggatt’s apple leafhopper (FAL) in Canterbury. The number of adults belonging to the first generation peaks mid December and the second during early March. In the IFP block, FAL numbers were reduced in the second generation, possibly due to the parasite Anagarus armatus. It is unclear why A. armatus didn’t control FAL on the BFP block - possibly the copper/ sulphur fungicides limited the parasite.
Scale insects
The researchers were unable to find any scale insects on the fruit at harvest. However, several scale crawlers were found on the BFP block. These crawlers may have come in from a nearby biological block which contains scale insects.
In summary
IFP appears to work well in Canterbury. After one season, there was very little insect damage on the Fuji harvested from the IFP block.
The major pests - leafrollers and codling moth - can be successfully controlled with three or four Mimic sprays. Predatory mites will successfully control plant-feeding mites. Other pests - woolly apple aphid, apple leafcurling midge, Froggatt’s apple leafhopper and scale - are so far under control. However, potentially some of these pest populations could increase to unacceptable levels. Therefore, it is vital that the natural pest enemy populations are able to build-up on the orchards. Avoiding organophosphate sprays will go a long way to helping increase the numbers of parasites and predators. In some cases predators will need to be introduced onto the orchard. In the absence of organophosphates, a balance between pests and predators will be reached on the IFP orchard.
Acknowledgments
HortResearch acknowledges ENZA New Zealand (International) and the Foundation for Research, Science and Technology for financial support.