Contents

Welcome

Ian Warrington, CEO HortResearch

New management strategies for black spot

William MacHardy, University of New Hampshire and Robert Beresford, HortResearch

New chemistry for black spot control

Dieter Mappes, BASF Germany

BASF fungicide trial

Peter Shaw, HortResearch

Future apple gene improvements

Lester Brewer and Peter Alspach, HortResearch

New pipfruit cultivars

Allan White, HortResearch

Intensive apple systems

John Palmer, HortResearch

Integrated Fruit Production Update

Jim Walker, HortResearch and Audrey Fell-Smith, pipfruit grower Nelson.

Futures for Fruit

Dorian Scott, HortResearch

Welcome

Recent successes that are already benefitting the pipfruit industry include:

• Development of the industry-wide Integrated Fruit Production (IFP) strategies with the supporting manual and grower discussion groups - so advancing progress towards sustainable production methods.
• The breakthrough in using molecular (DNA)-based techniques for mealy bug identification - easing the procedures for entry of fruit onto the important
  USA markets.
• Continued release of new cultivars from our breeding programmes for industry evaluation and adoption - providing unique opportunities for innovative product development on world markets.
• Continued support for the fire blight protocols being used for access to Japan and applications for access to Australia.

HortResearch acknowledges the significant support that it receives through research contracts from the NZAPMB, from Government through contracts from the Foundation for Research, Science and Technology, and from a wide range of commercial clients.

We invite you to fully participate in the field day programme. Seek answers to your questions, interact fully with our staff and guest speakers, and take advantage of the new opportunities being presented to the fruit industry.

Enjoy the day!

Dr Ian Warrington
Chief Executive Officer

New management strategies for apple black spot

The Integrated Fruit Production (IFP) initiative which has been introduced this season by ENZA has given a sharp focus to disease management research required to cope with stricter requirements for pesticide use in apples.

IFP does not necessarily mean that fewer fungicides will be used for disease control. The philosophy of IFP is that fungicides will only be applied where their use can be justified. This may lead to a reduction in fungicide use in some situations. We need ways to better assess disease risk so that fungicides can be applied more precisely when they are needed, however, any modification of standard spray programmes must ensure that there is no increase in risk of disease control failure.

Current research is developing methods to assess disease risk more accurately. This requires precise monitoring of disease activity in the crop to determine:

1) When weather is suitable for infection (weather stations and Mills' periods)

2) When ascospores are being released in spring (ascospore monitoring service)

3) Threshold disease levels to trigger appropriate fungicide responses, including:

a) black spot and powdery mildew levels at key growth stages

b) assessment of potential ascospore dose at leaf fall in autumn.

Potential Ascospore Dose (PAD)

Correct fungicide management requires information on numbers of ascospores available in spring in individual orchard blocks. This helps to determine whether or not a fungicide is needed in response to a particular infection period. Methods developed by Prof. MacHardy in New Hampshire will be evaluated under New Zealand conditions in a new research programme to be initiated this autumn.

PAD assessment involves determining the amount of black spot on leaves just before leaf fall in autumn and using a formula to calculate the potential number of ascospores that could be released the following spring. Included in the research programme will be a study of the the effectiveness of autumn urea treatment in reducing PAD and an evaluation of the possibility of using PAD and sanitation practices to delay or reduce the use of fungicides in spring.

New chemistry for black spot control

Stroby WG - a new fungicide for the control of scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) on apples.

Stroby WG, a fungicide from the strobilurine class, gives excellent control of
Venturia inaequalis and Podosphaera leucotricha on apples. Against V. inaequalis Stroby WG has a preventive effect, by preventing spore germination, and also curative effect in that it prevents further sporulation of the fungus. To achieve these effects, it should be applied as a block treatment consisting of several applications. The preventative and curative effects combined with its good rainfastness provide unusually long-lasting protection against leaf and fruit scab.

BASF Fungicide Trial

Two new fungicides from BASF (Scala and Stroby) for black spot and powdery mildew control in apples are being tested this year in field trials conducted by HortResearch in Nelson, the Hawke's Bay and Central Otago. The BASF programme is being compared with a standard Polyram-based programme in replicated field trials at each site. A third experimental treatment is looking at the BASF products used with a slightly extended spray interval. Treatments are being applied by standard air-blast sprayer (2500L/ha.).

The Nelson trial is being conducted on Royal Gala at Motueka, at a site which had high black spot levels last year. The accompanying tables show that in early December all three treatments had similar amounts of black spot on both leaves and fruit. The standard programme tended to have slightly more black spot, although the effect was not statistically significant.

Fruit russet did not differ significantly among the three treatments and powdery mildew control was as good in the BASF programme as the standard.

Mite counts during November, December and January showed that numbers of Typhlodromus pyri built up more in the two BASF programmes than in the Standard programme. This reflects the adverse effect of the Polyram in the Standard programme on
T. pyri numbers.

The results recorded this season confirm two previous season’s trial results which showed that both the Scala and Stroby fungicides provided excellent disease control under high black spot infection pressure.

Results

Nelson, Royal Gala - 3 December 1996

	Black spot and powdery mildew
Treatment	% of leaves on extension shoots with black spot	% of fruit attached to trees with black spot	% of leaves on extension shoots with powdery mildew
1. Standard	1.82	4.98	0.20
2. BASF	0.22	2.19	0.11
3. BASF Extended	0.22	2.63	0.33
Probability that differences occurred by chance	.162 NS	.177 NS	.500 NS
Unsprayed trees (not included in analysis)	48.3	71.7	2.7

NS =Treatment effect not significant, P>.05
* =Treatment effect significant, P<.05
Where the treatment effect was significant, means within columns accompanied by the same letter were not significantly different (P<.05)

Nelson, Royal Gala - 3 December 1996

	Fruit russet
Treatment	% of fruit with up to 10% russet	% of fruit with >10% russet	% of fruit with rough russet
1. Standard	3.3	1.3	0.0
2. BASF	4.3	1.5	0.0
3. BASF Extended	1.8	0.9	0.0
Probability that differences occurred by chance	.561 NS	.915 NS	-
Unsprayed trees (not included in analysis)	0.4	0.0	0.4

NS =Treatment effect not significant, P>.05
* =Treatment effect significant, P<.05
Where the treatment effect was significant, means within columns accompanied by the same letter were not significantly different (P<.05)

Nelson, Royal Gala - 5 November 1996

	Mite counts per 50 leaves
Treatment	European red mite (ERM)	ERM eggs	Typhlodromus pyri	T. pyri eggs
1. Standard	3	3	1	1
2. BASF	0	9	3	3
3. BASF Extended	0	0	5	4
Unsprayed trees	0	0	7	2

Nelson, Royal Gala - 11 December 1996

		Mite counts per 50 leaves
Treatment		European red mite (ERM)	ERM eggs	Typhlodromus pyri	T.pyri eggs
1. Standard	Rep 1 Rep 2	2 0	8 2	0 0	0 0
2. BASF	Rep 1 Rep 2	0 0	1 0	4 6	4 4
3. BASF Extended	Rep 1 Rep 2	1 0	1 0	4 9	3 6
Unsprayed trees		0	0	7	12

Nelson, Royal Gala - 13 January 1997

		Mite counts per 50 leaves
Treatment		European red mite (ERM)	ERM eggs	Typhlodromus pyri	T. pyri eggs
1. Standard	Rep 1 Rep 2	1 34	14 13	3 1	0 0
2. BASF	Rep 1 Rep 2	2 2	14 5	22 23	18 9
3. BASF Extended	Rep 1 Rep 2	6 0	12 4	20 7	11 4
Unsprayed trees		0	1	38	9

BASF trial 1996-97, Nelson: Early-season spray dates

	Royal Gala
Date	Growth stage	1. Standard	2. BASF	3. BASF extended
September 1996
16	green tip	dodine (80ml)	Nustar (15g)	Nustar (15g)
23	open cluster	dodine (80ml)	Nustar (15g)	Nustar (15g)
October 1996
1	pink	dodine (80ml)	Nustar (15g)	Nustar (15g)
9	bloom	Polyram (125g) Pallitop (50g)	Scala (75ml)	Scala (75ml)
18	bloom	Polyram (125g) Pallitop (50g)	Scala (75ml) Pallitop (50g)	Scala (75ml) Pallitop (50g)
29	petal fall	Polyram (125g) Nustar (10g)	Stroby (10g)	Stroby (10g)
November 1996
6		Polyram (125g) Pallitop (50g)	Stroby (10g)
8				Stroby (10g)
13		Polyram (125g) Nustar (10g)	Stroby (10g)	Stroby (10g)
20		Polyram (125g) Nustar (10g)	Stroby (10g)	Stroby (10g)
28		Polyram (125g) Pallitop (50g)	Stroby (10g)
December 1996
2		Captan (100g) Systane (11g)	Stroby (10g)	Stroby (10g)
13		Captan (100g) Pallitop (50g)		Stroby (10g)
19		dodine (80ml)	dodine (80ml)	dodine (80ml)
31		dodine (80ml)	dodine (80ml)	dodine (80ml)
January 1997
13		dodine (80ml)	dodine (80ml)	dodine (80ml)

Future Apple Gene Improvement

This programme is designed to give genetic information, and to develop a diverse base population of reasonable quality apples for use as future breeding parents. Base population development is the core of success in breeding. There is a lot of germplasm in collections like pieces in a museum - nice to look at, but not of much use. They will never be used in breeding programmes until they’re the equivalent of the elite parents currently in use (Hallauer in Stalker & Murphy 1991, pp97-98).

The entire first generation of open-pollinated seedlings from approximately 500 families has been planted over the past four years. Approximately half the trees are located at Havelock North, and a quarter each at Riwaka and Clyde. Seedlings for the first three planting years came mostly from collections of diverse varieties held in various research institutes around the world. The final planting, of approximately 4,000 trees, originated from seeds of fruit collected from promising trees in the population of wild apples in Kazakstan.

Budburst for the trees from the first planting at Riwaka ranged over 2½ months, beginning late August/early September. The range within individual families was less: up to 7 weeks. In 1996, the first flower opened in mid-September for the earliest tree, and mid- to late-November for the latest tree.

Picking date ranged from 12 January to 1 May for the fruit harvested in 1996 across all sites (approximately 10% of the trees from the first year of planting). The range within individual families was up a little over 3 months. Average fruit size ranged from less than 1g to more than 375g; the fruit size range within individual families was up to almost 300g. The fruit size distribution was bi-modal, with a peak around 5g representing the crabs, and another at about 130g. Soluble solids at harvest ranged from a little under 6% to over 20%, and pH varied from 2.7 to 5.8.

Tree girth measurements on the first year’s trees suggested that the relative vigour of the families varied between sites. For example, family 91.174 was one of the smaller trees at Riwaka, but one of the larger at Havelock. However, further analysis needs to be done to investigate this genotype by environment interaction.

At Havelock, attack by woolly apple aphid and powdery mildew has been evaluated on the first planting. The majority of the families had two thirds of the trees affected by woolly apple aphid. However, 12% of the families had more than three quarters of the trees unaffected. All trees from 10% of the families were free of powdery mildew.

Some fruit from early trees will be on display, and photographs representing some of the diversity will be available.

References

Stalker, H.T.; Murphy, J.P. (eds) 1991: Plant breeding in the 1990s: Proceedings of the symposium on plant breeding in the 1990s. CAB International Oxford, UK.

New releases from the pipfruit breeding programme

Presented by: Allan White
HortResearch
Hawke’s Bay Research Centre

Pear Breeding

Pear breeding began at Havelock North in 1983 with a series of crosses between Japanese and European cultivars. Since then over 100 different crosses have been made here and at HortResearch Riwaka, where the programme is now based. Parents used in crosses include European, Chinese and Japanese cultivars.

The major objective of the programme has been to develop a new range of cultivars which combine crisp flesh and high flavour.

Selections of all three types as well as novel interspecific selections have been evaluated on HortResearch stations from Kumeu to Clyde and several are now being bulked up in conjunction with ENZA and FIPIA for testing on commercial orchards.

Other interesting fruit character combinations featured in our display include red colour with round Japanese pear fruit-shape and a range of fruit-shape from pyriform to round which has allowed us to make selections distinctively different in looks from existing cultivars.

New releases from the pipfruit breeding programme

New apple and pear selections from the HortResearch Breeding Programme recommended for trialling on commercial orchards since 1994 include:

Apples

A20R02T032: A yellow apple with an orange blush on exposed fruit. Flesh is very crisp, sweet and has long storage potential. Seen as a possible alternative to Orin. Harvest
mid-March.

A20R02T273: An attractive orange red stripe with crisp tangy flesh. Very good storage performance. Harvest early March.

GS494: Bright red block colour on cream background. Good flavour and storage. Harvest 10 days before Gala.

Pears

P098R01T045: Round-oval, red skinned, crisp flesh. Full WBC aroma. Long storage potential, good shelf-life. Harvest mid-February.

P037R48T106: Attractively blushed green-yellow pear with crisp juicy flesh. Refreshing flavour, good storage. Harvest mid-January.

P037R48T81: Attractively blushed yellow-green fruit. Sweet crisp flesh, good storage potential. Harvest early February.

Intensive apple orchards on M.9 rootstock

Intensive systems on dwarfing rootstocks have dramatically altered the nature of apple growing in Europe and are beginning to have a similar impact in parts of North America. These systems have been adopted because they result in early cropping, improved fruit quality and decreased costs of production. There is a growing interest in these systems in New Zealand and several years ago Dr Stuart Tustin established a network of trials of ‘Fuji’ on dwarfing and semi-vigorous rootstocks. These trials have used Mark and M.26 as dwarfing rootstocks. Virus-free M.9 has now become available and it seemed prudent to examine the performance of trees on M.9 as it is used so successfully elsewhere in the world.

Ideally, intensive systems should begin with well-feathered trees. Table 1 gives a comparison of fruit numbers on well- and non-feathered trees of ‘Fuji’ and ‘Royal Gala’ in years two and three in the orchard and shows the very substantial yield advantage of well-feathered trees.

Table 1: Effect of tree quality on early yields of ‘Royal Gala’ and ‘Fuji’ on M.9 rootstock. Poor quality trees were unfeathered whips while good quality Royal Gala trees had a mean of 8.6 feathers and good quality Fuji trees had a mean of 6.8 branches at planting.

As there is so little experience of the vigour of trees on virus-free M.9 in New Zealand, a spacing trial was planted at Riwaka using well-branched trees of three scion cultivars in 1993. Row spacing is 3.5 m and the trees are pruned to slender spindles. This trial on the research orchard has been supplemented by grower trials on a number of sites in Nelson and Blenheim. The work also has obvious cross links to the apple rootstock and interstock work being carried out in Nelson, the Hawkes Bay and Clyde. The tables below give the cropping and fruit quality results to date i.e. years two and three.

Table 2: Mean yield per tree (kg) of three cultivars at four within-row spacings on FKV M.9 in the second year.

Table 3: Calculated yield per hectare (tonnes/ha) of three cultivars at four within-row spacings on FKV M.9 in the second year.

Table 4: Mean fruit weight and percentage export pack out of three cultivars on FKV M.9 in the second year.

Table 5: Mean yield per tree (kg) of three cultivars at four within-row spacings on FKV M.9 in the third year.

Table 6: Calculated yield per hectare (tonnes/ha) of three cultivars at four within-row spacings on FKV M.9 in the third year.

Table 7: Mean fruit weight and percentage export pack out of three cultivars on FKV M.9 in the third year.

Mean yields of 10 kg per tree in the second year and 20 kg per tree in the third year are encouraging but the poor grade out of ‘Fuji’ due to russet is disappointing. There have been no statistically significant effects of spacing on growth or yield per tree to date in this trial but this effect would be expected to appear as the tree canopy develops further.

Although intensive systems can produce early yields, fruit from young trees has traditionally not been exported from New Zealand due to a perception that fruit from young trees has poor storage life. Records of fruit quality after storage, when the trees on the M.9 spacing trial were two-year-old, showed excellent quality with low levels of storage disorders.

Tree to tree variability has been high on this plot reflecting the soil variability, consequently these yields reported here are probably somewhat conservative and would be expected to be higher in more uniform, fertile soils.

Integrated Fruit Production

Approximately 80 orchards around the country are involved with the ‘pilot’ Integrated Fruit Production (IFP) programme. These orchards are evaluating the proposed pest management procedures including pest monitoring methods and thresholds. The Hawkes Bay and Nelson field days present current research into IFP pest management which may be adopted as part of the programme.

Leafroller and codling moth
The basis of leafroller and codling moth control in the IFP programme is tebufenozide (Mimic) but alternative products (eg lufenuron or Match), which are also highly selective, are being assessed for insect control and tools to manage any potential for resistance in these new selective insecticides. Leafroller treatment response thresholds are also being tested against the current threshold of one infested/damaged shoot (or fruit) per 200 against one per 400.

IFP programmes are also being monitored on commercial orchards in Nelson and Hawkes Bay. In one sample of seven Hawkes Bay IFP growers, with a total of 30 separate cultivar blocks, an average of 2.4 insecticides per block had been applied between petal-fall and January 20, 1997. Growers report finding low levels of insect damaged or infested fruit during their regular monitoring programmes.

Woolly apple aphid
Woolly apple aphid (WAA) can be a serious pest of apples but is usually partially suppressed by frequent applications of organophosphate (OP) insecticides. IFP is based on selective pesticides for codling moth and leafroller control so, in the absence of OP sprays, WAA can increase to very damaging levels. IFP research is evaluating control of WAA with new aphicides and biological control with Aphelinus mali, the parasitoid of WAA. Trial results show that once it is established within a block, A. mali can provide effective biological control of WAA provided control is not disrupted by some pesticides.

Many pesticides have been screened for their effect on A. mali. Most have little effect on the parasite but chlorpyrifos, (eg Lorsban), diazinon (eg Basudin) and carbaryl (eg Basudin) are disruptive. Trial results show carbaryl to be highly disruptive to biological control and contributing towards WAA outbreaks. As long as these compounds are used in NZ apple production selective aphicides will be required. Three new aphicides one foliar and two soil applied are also being evaluated for WAA control, one of these pirimicarb (Pirimor) is selective and should be registered for use on apples within the near future.

Leafhoppers
Leafhopper populations are being monitored in IFP trial blocks at Havelock North and Nelson. Buprofezin (Applaud) and chlorpyrifos are being evaluated for early season control.

Beneficial species
Many different species of natural enemies are thought to be important in biological control of key orchard pests. Apart from A. mali and Typhlodromus pyri, other important natural enemies have been identified such as spiders, earwigs, lacewings and predacious mirid bugs.

IFP pest management research trials are being conducted at both Havelock North and Appleby research orchards to identify the important regional differences in pest management. All aspect of these trials will be presented and summary results of graphical presentations will be provided.

Futures for Fruit

Futures for Fruit is an industry foresight project that aims to improve the profitability of growers through better long term planning. This project was initiated in March 1996 by HortResearch and New Zealand Fruitgrowers Federation and culminated last year in the NZ Fruitgrowers Federation Annual Conference. At this Conference a number of possible scenarios for the future of the NZ fruit industry were studied.

Foresight is imagining the future. Foresight acknowledges that there are sudden market changes and technology leaps which make forecasting unreliable in today’s environment. Foresight looks beyond the normal horizon of 3-5 years to a future 10 to 15 years from now. The aim of the Futures for Fruit Foresight project is to build the most accurate picture of the future and thereby be in a position to feed this into the various planning processes across the whole industry. Our project goal is:

To identify and secure long-term sustainable competitive advantage for the New Zealand Fruit Industry

Industry Foresight ensures future competitive advantage by helping to answer the questions;

• what new types of customer benefits will be desired
• what new skills, technologies, resources and capabilities will be needed to offer those benefits;
• how will we need to reconfigure the customer interace to meet future needs.

The New Zealand Fruit Industry faces incredible challenges over the next 10 years. Grower responsibility and accountability for product quality will increase. However, it will not be sufficient to just produce high quality fruit at the packhouse. All parts of the industry will need to predict shifts in the market place and thereby plan changes in production practices to meet future market requirements. Likewise the impacts of the market place will be felt both directly and indirectly by all related service, research and marketing businesses.

There is a limit to what can be achieved by either incremental quality and efficiency improvement or by focusing on removing costs from the industry. Future success will come from bold strategy initiatives that focus on value added and market leadership. Foresight enables an industry to get to the future first and to help create that future.

Increasing global competition in our industry poses great threats to those who are not prepared. Whilst New Zealand has a number of unique advantages, success in the marketplace will only come from creating new competitive space. Much of the success in doing this will depend on good industry foresight and effective investment. The project team is planning to hold a workshop with a few key industry people in order to develop a five year Strategic Plan for the fruit industry. This Plan will be a bold visionary document that will illustrate what can be achieved by industry-wide planning. This will be a key document for the fruit industry in New Zealand to improve its competitive position over the next 5 years and to increase returns to growers.

Sponsors of the Futures for Fruit foresight project in 1996 were:
HortResearch
NZ Fruitgrowers Federation
NZ Kiwifruit Marketing Board
ENZA New Zealand (International) Ltd
Pipfruit Growers of NZ Inc.