Consumer acceptance study of early marketed Forelle pears in the United Kingdom and Germany, IJ Crouch, H Bergman

Tags: South Africa, respondents, Germany, hedonic scale, Forelle pears, Forelle pear, diagnostic scale, vivo production, harvest, commercial harvest, acceptance, consumer ratings, nematode species, insect pests, penalty points, United Kingdom, Fruit Technology Solutions, rating, cold storage, reasonable price, Human Resources for Industry Programmes, National Research Foundation, soilborne pests, Citrus Research International, Pear Producer's Association, product characteristics, production process, consumer acceptance, laboratory culture, wooden boxes, South African, Stellenbosch University, Department of Conservation Ecology, Forelle Producers Association, codling moth, juicy fruit, the United Kingdom, storage period, attributes, Juiciness, crispness, Wax moth larvae, EPN, mass production, developing countries, insect host, susceptible host, biological control agent, biological control agents, insect hosts
Content: FRUITGROSCIENCE Consumer acceptance study of early marketed Forelle pears in the United Kingdom and Germany IAN CROUCH & HELEEN BERGMAN ExperiCo (Fruit Technology Solutions), P O Box 4022, Idas Valley, Stellenbosch, 7609, South Africa. Research financed by FruitGroScience on behalf of the South African Apple and Pear Producers' Association and AgroFresh Inc.
Introduction This feedback is a follow up to an earlier article (Crouch and Bergman, 2010), where it was proposed that Forelle pears, in selected orchards, be held on the trees for 2 or 3 weeks past the typical commercial harvest date and then be subjected to a SmartFreshSM application to prevent ripening, thereby enabling the earlier marketing of a crisp but sweet and juicy fruit. This publication was delayed from 2011 to 2012, and a 2012 update publication will be made in 2013. Forelle pears grown in South Africa are prone to mealiness and astringency if not cold stored for at least 12 weeks at -0.5°C. This mandatory storage period can result in a gap between the last bicolour pears, such as Rosemarie and Flamingo, and the availability of Forelle in the market place. Loss of South African bicolour pear continuity may result in buyers switching to fruit from other offshore competitors, a move that often remains permanent, even when Forelle pears from South Africa become available. This problem is exacerbated by fruit arriving in Europe from South America several weeks earlier than the first South African Forelle, mainly because fruit from these countries are packed and shipped immediately after harvest. Chilean export volumes of Forelle have seen a sharp year on year increase in volumes. An urgent need has therefore arisen for SA Forelle to be available in Europe from week 15. The objective of this research initiative was therefore to reduce the mandatory 12 week cold storage period following Forelle harvest and enable availability of acceptable eating quality South African Forelle pears in Europe from week 15, after only 4 to 6 weeks cold storage. Consumer acceptance of the early marketed Forelle was assessed by Wirral Sensory Services Limited in the United Kingdom, and Eurofins ­ Wiertz-Egget Jцrissen, in Hamburg, Germany. The cost of these surveys was graciously paid by AgroFresh Inc., the suppliers of SmartFreshSM. Three exporters participated in the trial, with fruit being sourced from four geographical regions, and packed in five shipping containers: · DuToit fruit from the Langkloof were sent to France and distributed by Pomanjou in the Loire Valley. · Tru-Cape fruit from Ceres (Ceres Fruit Growers) were sent to Rotterdam, and samples trucked for examination to the Capespan office in Hamburg Germany. · Tru-Cape fruit from Elgin (Two-A-Day) sent to the UK and distributed by Chingfords for Sainsbury. · Fruitways fruit from Graymead Farm in the Vyeboom were 64 SA FRUIT JOURNAL DEC/JAN 2013
packed at Elgin Orchards and sent to the UK where they were received by Mack Multiples for Sainsbury. · Fruitways fruit from Graymead Farm in the Vyeboom were packed at Elgin Orchards and sent to Hamburg, Germany, where they were marked by EDEKA. Methodology Research over the last few years has concentrated on ways to shorten the initial cold storage requirement of Forelle, and still maintain fruit of exceptional shelf life and eating quality. To this end, ExperiCo (Fruit Technology Solutions) has conducted trials over several seasons and developed a method with potential to provide a good eating quality Forelle pear that can be sold within 4 weeks of harvest. The harvest of fruit from selected orchards was delayed for 2 to 3 weeks after the normal commercial harvest, therefore allowing the fruit to approach an acceptable eating quality on the tree, with sugar levels above 14%, and flesh firmness targeted between 6.0 and 5.5 kg (Table 1). Fruit were then subjected to a SmartFreshSM application within 7 days of harvest to delay fruit ripening, packed immediately and cold stored for a minimum of 4 weeks at ­0.5°C at the ExperiCo facilities in Stellenbosch, or containerised and shipped to the UK or Europe immediately after packing. A replicated set of samples from each orchard was packed into the container destined for Mack Multiples in Liverpool, and examined by ExperiCo at the port of destination during week 17. At this time, the bulk of the fruit had already been distributed to Sainsbury stores and sold. Samples of fruit were also examined by ExperiCo in Germany at the Capespan and EDEKA offices in Hamburg. Holdback samples in South Africa were examined at the same time as the offshore samples, with the added advantage that these examinations also included untreated controls to determine the ripening trends of the fruit had they not been subjected to SmartFreshSM. Results indicated that after 4 to 6 weeks cold storage, the fruit developed unacceptably high levels of mealiness in the absence of SmartFreshSM, regardless of growing area (Figure 1). The quality of the SmartFreshSM treated fruit examined offshore was similar to the holdback samples assessed in South Africa. Fruit were consistently crispy and sweet and seldom dry or mealy (Table 2). Although some astringency occurred, levels were very low and mainly restricted to fruit from the Vyeboom orchard. A shelf-life ripening period resulted in a slight
FRUITGROSCIENCE
Table 1: Harvest, shipping and maturity information of Forelle pears used in semi-commercial trials, when harvested 2 to 3 weeks after the commercial harvest.
Maturity Parameter Langkloof
Harvest Week Shipping Week On Arrival Week Starch breakdown (%) Flesh firmness (kg) Skin ground colour1 Red skin colour1 Total soluble sugars (%) Titratable acidity (%)
10 12 14 15.8 5.8 2.8 3.0 14.8 ­
Ceres 11 12 15 0.0 5.9 2.6 7.7 14.2 0.26
Elgin Vyeboom
11 12 15 ­ 5.8 ­ ­ 15.1 ­
11 12 15 0.0 6.1 3.1 6.2 13.9 0.22
Table 2: Fruit quality of Forelle pears subjected to SmartFreshSM examined in the United Kingdom and Germany after ± 6 weeks RA storage at -0.5°C followed by a shelf life period of 7 days at 20°C.
Exporter
Flesh
Skin
TSS Astring-
Firmness Colour (%)
ency
(kg) (%)
Langkloof
SOS
5.9
EOS
5.9
Vyeboom UK
SOS
5.7
EOS
5.8
Vyeboom EU
SOS
5.9
EOS
5.1
Elgin
SOS
6.0
EOS
6.0
Ceres
SOS
5.9
EOS
5.9
1.6
14.9 0.0
1.8
14.7 0.0
2.3
16.7 0.0
2.7
16.5 0.0
1.9
16.7 4.0
2.2
16.6 0.0
1.6
15.8 0.0
1.9
15.4 0.0
2.1
16.6 2.0
2.2
16.6 6.0
Mealiness (%) 0.0 0.0 0.0 4.0 0.0 0.0 0.0 0.0 0.0 2.0
Figure 1: Incidence of mealiness in Forelle pears not subjected to SmartFreshSM when stored in South Africa under RA conditions at -0.5°C for 6 weeks followed by a shelf life period of 7 days at 20°C. advancement in skin ground colour, but fruit remained firm and did not ripen and become mealy. Although the fruit exhibited some free juice, this was never to the extent as that found in ripe, non-mealy pears. Consumer Acceptance Survey Critical to this study were the consumer acceptance surveys conducted by specialist taste panels in Wirral in the United Kingdom (UK) and in Hamburg, Germany. A Central Location Test of 98 typical consumers was carried by Wirral Sensory Services Ltd, with respondents a mix of ages and socio-demographics. Respondents were asked to score the product for a number of key parameters on a 10-point hedonic scale and to score the product on a 5-point diagnostic scale for certain parameters such as sweetness, sourness, crispness and juiciness. A test of 101 typical consumers was carried out in Hamburg by Eurofins Analytik GmbH Wiertz-Eggert-Jцrissen, with respondents of a mix of ages and socio-demographics. The questionnaire included a mix of hedonic questions and just-aboutright questions. The sensory acceptance of the pear was assessed, using the 9-point hedonic scale outlined in Table 3. Just-about-right-questions are used in consumer tests in addition to the hedonic questions. This makes it possible to evalu-
ate specific product characteristics and to identify potential product-problems. In the present case, the attributes sweetness, sourness, juiciness and crispness were assessed via just-aboutright questions. They were evaluated, using the following scale: 1 = much too weak 2 = too weak 3 = just about right 4 = strong 5 = much too strong
When evaluating the just-about-right data, the penalty analysis is used. By calculating penalty points, the individual product characteristics are evaluated. The aim of this method was to identify the product characteristics that affected its acceptance and to analyze in which dimension they affected the acceptance. The size of the impact is illustrated by the calculated penalty-points.
Table 3: The structure of the 9-point-hedonic-scale to ascertain sensory acceptance.
Classification of the acceptance
9
like-very-much-category
8
9-point-hedonic-scale Like extremely Like very much
7
like-category
6
Like moderately Like slightly
5
neutral category
Neither like or dislike
4
dislike-category
3
2
1
Dislike slightly Dislike moderately Dislike very much Dislike extremely
65 SA VRUGTEJOERNAAL DES/JAN 2013
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Thus, one gets information about critical product characteristics, in order to perform specific product modifications. The extent of the penalty-points gives information, as to whether the product differs in certain characteristics from the ideal, and to whether corrective action is required (Table 4). Regardless of country, all respondents were asked to indicate what type of pear they preferred, how the product compared to others currently on the market and whether they would buy the product if it was available at a reasonable price.
Figure 2: United Kingdom consumer ratings for different sensory attributes of SmartFreshSM treated Forelle pear when measured using the 10-point hedonic scale. Fruit falling above 7.0 on this scale indicate a favourable response from respondents.
Table 4: Rules used to assess penalty points.
The majority of respondents stated that they thought
Penalty Points To Do
the Forelle pear overall quality was equal to other va-
>40 40 ­ 80
negligible product should possibly be changed
rieties of pear currently on the market (Table 6), and a significantly higher number of respondents indicated they would purchase the Forelle pear at a reasonable
>80 to improve the acceptance of the product, it should be changed
price if it was available on the market. This was par-
ticularly interesting as 50% of the respondents pre-
ferred a softer pear in the pre-tasting analysis, and
Results and comments of the United Kingdom consumers yet after tasting the crisp, sweet Forelle pear, the majority of tast-
Respondents were predominantly female and although there ers indicated that they would buy this firmer fruit.
were representatives from a range of age groups, almost 30% of the consumers were above 65 years old (Table 5). Almost twice as many respondents indicated that they preferred a softer pear to that of a firmer pear in the pre-tasting question. The Forelle Pear achieved excellent scores for overall appearance, overall flavour, sweetness and crispness and very good scores for overall acceptance, sourness, overall texture and juiciness (Figure 2). A "just right" score was achieved for sourness, and overall quality could be improved by slight increases to both the sweetness and juiciness and a slight decrease to the crispness (Figure 3). Table 5: Comparison between gender split, age group range, and eating preferences between respondents from the United Kingdom
Results and comments of the German consumers Respondents were also predominantly female and although there were representatives from a range of age groups, the majority of consumers were between 20 and 40 years old (Table 5). Contrary to the UK consumers, the majority of German respondents indicated that they preferred a firmer pear to that of a softer pear in the pre-tasting question. The Forelle pear achieved excellent average scores for overall appearance (7.4) and sweetness (6.8), with all other sensory attributes falling within the "like" category (Figure 4). The highest score for the "like very much" category was for crispness. From
and Germany.
Table 6: Consumer preference for SmartFreshSM treated Forelle pear,
UnitedGermany
compared to similar pears currently available in the market, and their
Kingdom
willingness to purchase the fruit at a reasonable price.
Gender Age Group Firmness Preference
Male Female Under 25 25-34 35-44 45-54 55-64 Over 65 Soft Firm Neither
35
Male
63
Female
12
Under 20
5
21-30
14
31-40
22
41-50
16
Over 50
29
50
Soft
26
Firm
22
Neither
37
United Kingdom
Germany
64
The respondents were asked how they would rate the pear to other
1
varieties currently on the market
36
31
Better
14
Equal
16
Worse
22
32
46
49
30
20
The respondents were asked if they would purchase the pear at a
42
reasonable price
50
Yes
9
No
61
66
37
35
66 SA FRUIT JOURNAL DEC/JAN 2013
FRUITGROSCIENCE
Figure 3: United Kingdom consumer ratings for sweetness, sourness, crispness and juiciness of SmartFreshSM treated Forelle pear when measured on the 5-point diagnostic scale, where a rating of 3 indicates that the attribute is close to "just right".
the "just-about-right" questions, although the analysis found that the sweetness and sourness attributes of the pear were acceptable, the points for crispness were above 80 indicating that to improve the acceptance of the product, some changes were necessary (Table 7, Figure 5). Juiciness was also rated as requiring some slight improvement. Re-analysing texture and crispness attributes by ignoring those respondents that preferred a softer pear, resulted in texture and crispness scoring an average of 7.2 and 7.5, respectively on the hedonic scale, but more importantly reducing crispness from 102.2 to 51.7 penalty points on the just-about-right diagnostic test (Table 5). Like their UK counterparts, the majority of German respondents stated that they thought the Forelle pear was equal or better than other varieties of pear currently on the market, and a significantly higher number of respondents indicated that they would purchase the pear at a reasonable price if it was available on the market. In conclusion, regardless of country, the Forelle pear scored extremely well in terms of hedonic and diagnostic results, and although some tasters preferred a softer pear, they rated it equally Table 7: German consumer penalty point ratings for sweetness, sourness, crispness and juiciness of SmartFreshSM treated Forelle pear when measured using the just-about-right data, where a rating of below 40 points indicates that the product does not require any change, a rating of between 40 and 80 points indicates that the product could possibly undergo some minor changes, and a rating above 80 indicates that to improve the acceptance of the product, some changes are necessary.
All respondents Rating
Respondents that prefer firmer fruit
New Rating
Sweetness
15.3 < 40
Sourness Crispness Juiciness
23.5 < 40 102.2 > 80 X 71.7 40 ­ 80 ?
51.7 40 ­ 80 ?
Figure 4: German consumer ratings for different sensory attributes of SmartFreshSM treated Forelle pear when measured using the 9-point hedonic scale, where a rating of 1­4 falls within the dislike category, a rating of 5 the neutral category, 6-7 the like category, and 8-9 falls within the like very much category. Figure 5: German consumer ratings for different sensory attributes of SmartFreshSM treated Forelle pear when measured using the 5-point diagnostic scale. compared to other pears on the market. However, there does seem to be room for improvement, one notable area being that the pear was considered slightly too crisp which resulted in the pear not being juicy enough. This was supported by the fact that many comments said the firmness of the pear was a particular issue. South African Marketing Strategy ­ the way forward Making this a successful programme is all about managing the risk. While over 60% of consumers said that they would buy the fruit if it were available at a reasonable price ­ what about the 30 to 40% who didn't enjoy the eating experience? Would these consumers complain and compromise this initiative? It would therefore be important to discourage those shoppers who prefer a softer pear from eating a fruit that they would not enjoy. This could be done through "in-store" promotions where consumers could pre-taste the product before buying it, or by incorporating educational labels on the fruit or packaging that could read "Best Enjoyed Firm". The risk could be further managed by sending the fruit to correct target markets where consumers prefer a firmer, crisper pear. The roll-out of this programme on a larger scale would need to take several factors into consideration. The market strategy would need to be sanctioned by SAAPPA in CONTINUED ON PAGE 71 67 SA VRUGTEJOERNAAL DES/JAN 2013
FRUITGROSCIENCE
Cost-effective culturing of the yellow mealworm and greater wax moth larvae, for the in vivo production of a Biological Control agent: entomopathogenic nematodes CAROLIEN VAN ZYL & ANTOINETTE P. MALAN Department of Conservation Ecology and Entomology, Faculty of AgriSciences, Stellenbosch University
The establishment and maintenance of insect colonies is vital to the advancement of biological insect-control techniques and has lately especially been used for sterile insect release (SIR) purposes. The first step in the in vivo production process of entomopathogenic nematodes (EPNs) for use as biological control agents is the rearing of susceptible hosts. In order to produce EPNs of consistent quality, a continuous source of host insects reared on a standardised diet is required. Wax moth larvae (Galleria mellonella L.) and mealworms (Tenebrio molitor L.) were selected as hosts in the current study for the two endemic EPN isolates used, Heterorhabditis zealandica and H. bacteriophora. Each host was reared on a specific diet under optimal ambient conditions. The culture method that was used is easily reproducible, practical and can produce insect hosts on a small scale over an indefinite period of time. Introduction Annually, insect pests cause serious damage to agricultural crops, which leads to substantial financial losses in agriculture worldwide. In order to control such pests, humankind has tended to rely heavily on synthetic chemical pesticides. Although chemical pesticides have played an important role in controlling agriculturally important pests, their use has also led to pesticide resistance, secondary pest outbreaks, pesticide residues on crops, and health risks to animals and humans. Pesticide availability is also becoming increasingly restricted, as a result of more stringent safety requirements, which have led to the banning of many products. The negative consequences, and the current status, of synthetic compounds have contributed to an increased interest in adopting natural approaches. Such approaches are based on the development and incorporation of more environmentally benign alternatives in pest management practices. Biological control is one such alternative and, as a component of a pest management programme EPNs can be periodically introduced to maintain host population levels below what they would be in the absence of the nematodes. Entomopathogenic nematodes EPNs are naturally occurring, non-segmented, colourless, elongated, insect-parasitic roundworms, living in a variety of soil types and possessing the ability to infect over 200 insect hosts under laboratory conditions. The free-living, non-feeding infective juvenile (IJ), which is the invasive stage in the life cycle of EPNs, is used for insect control purposes. Once the IJ comes into contact with the host, depending on the specific species, it enters the insect through natural openings (mouth, anus, spiracles) or the body wall. The nema- 68 SA FRUIT JOURNAL DEC/JAN 2013
todes feed on the bacteria cells and metabolised host tissue, developing and reproducing within the insect cadaver for as long as nutrients are abundant. When all the nutrients have been consumed, the EPNs exit the cadaver in search of a new susceptible host. Apart from EPNs being especially efficacious against soilborne pests, they also show great potential for suppressing pests above ground via foliar application. In addition to EPNs being able to suppress pests within one to two days, they also have the ability to persist for two to three weeks in the field. Isolates of Heterorhabditis bacteriophora and Heterorhabditis zealandica, which have been collected during surveys conducted in South Africa, have been identified as being very effective against key insect pests of deciduous and citrus fruits. The insect hosts that were cultured in the current study were selected due to their proven high susceptibility to the two above-mentioned nematode species. EPN production One of the prerequisites for a biological control agent to be successful is the need to be capable of replicating it artificially in high numbers. EPNs can be cultured using either in vivo or in vitro technology. In vivo technology involves the inoculation of a susceptible insect host with the desired nematode to be replicated. As the insect host serves as a bioreactor, in which nematodes multiply, a large number of hosts are required for in vivo mass production of EPNs. High-quality nematodes are produced in such a manner. The number of nematodes that is produced in vivo is sufficient for use by the local market, in order to supply an inoculum for small-scale field trials and for the maintenance of laboratory cultures. In vivo production is a low-tech, albeit labour-intensive, process and is easily implemented in research laboratories, cooperations, cottage industries, and in such developing countries as South Africa, where labour is still relatively inexpensive compared to labour costs in first-world countries. Compared to in vivo production, in vitro production is a highly mechanised, capital-intensive, high-tech process, which is ideal for the commercial mass production of EPNs. As soon as higher numbers of nematodes are required, for example with orchard application, in vitro production is a more practical option, as large numbers of IJs can be efficiently produced in fermenting tanks. Nematodes have been commercially developed in North Amer-
FRUITGROSCIENCE
Wax moth larvae.
Above left: A wax moth larvae infected with entomopathic nematodes. Right: Wax moth larvae in diet.
ica, Europe, Australia and Asia for the control of a vast array of pests, ranging from pests occurring in greenhouses to those occurring on golf course turfs. Some of the pests concerned include citrus root weevils in citrus, black vine weevils in nurseries, mole crickets on turf grass, peach borer and codling moth on apples, and black cutworms. Biotechnological equipment and technical expertise regarding in vitro EPN production is, unfortunately, limited in South Africa and the commercial in vitro production of nematodes has yet to see the light of day in the country. In the interim, in vivo culturing methods are used in laboratories for experiments and small-scale field trials. In South Africa, research into the use of EPNs has been undertaken regarding the control of codling moth; mealybug; the banded fruit weevil; and false codling moth. Specific nematode isolates have been identified as promising biological control agents against the pests. Hopefully, in vivo production can be used as a stepping stone that could soon lead to the development of in vitro culturing of indigenous nematode species for the commercial market in South Africa. Insect hosts The most general and widely used host for in vivo EPN production is the greater wax moth (Galleria mellonella L.) larvae. Wax moth larvae are a major pest in apiaries, causing severe damage to stored and unattended honeycombs. In addition to being highly susceptible to nematodes, wax moth larvae are widely available, and can easily be reared on artificial diets within a relatively short space of time. The late-instar larvae pro-
duce sufficient numbers of nematodes to make their use feasible for in vivo production. Another promising host for nematode production is the yellow mealworm, Tenebrio molitor (L.). Mealworms are general decomposers and pests on poultry farms and in grain storage facilities. In most aspects, they measure up to wax moth larvae as being stellar hosts, yet they are less susceptible to nematodes when compared to such larvae, and also tend to produce fewer nematodes per host. Rearing of wax moth larvae Wax moth eggs and larvae obtained from the initial laboratory colony were placed on top of an artificial diet in well-ventilated plastic containers measuring 11 x 11 x 7.5 cm (length x width x height). The artificial diet consisted of 118 g wheat flour, 206 g wheat bran, 118 g milk powder, 88 g brewer's yeast, 24 g wax powder, 175 ml honey and 175 ml glycerol. The plastic containers were modified by inserting mesh screen into the lid to facilitate air and heat exchange, with the aim of avoiding condensation. The life cycle of wax moth larvae includes an egg, a larva, pupa and moth stage, and development took place at an average temperature of 26°C and at an average relative humidity (RH) of 55%. Moths were regularly removed from the diet as they hatched one to two weeks after pupation. They were then placed together in glass jars containing pleated wax paper, which served as an oviposition site for the female moths. The moths, which started laying eggs three to five days after emergence, had an average life span of one to two weeks at 26°C. Eggs were regularly removed from the paper with a razor blade and transferred to a plastic container, CONTINUED ON PAGE 71
Mealworms.
Wax moth larvae eggs being placed on top of the diet in ventilated plastic containers. 69 SA VRUGTEJOERNAAL DES/JAN 2013
FRUITGROSCIENCE
CONTINUED FROM PAGE 69 containing 1 kg of fresh diet. Eggs hatched within four to five days after being laid. The diet was replenished as needed to ensure the availability of sufficient nutrients for the larvae. The larval stage lasted between 20-40 days, after which time the larvae not used in experiments pupated, and the life cycle, which took six to seven weeks, was repeated. Rearing of mealworms Mealworm larvae, which were obtained from a laboratory culture, were reared on wheat bran as culture medium in various sized wooden culture boxes, which were covered with a solid lid to limit the amount of light penetration. Bran was frozen before use to prevent mite infection. Sufficient wheat bran (1 kg) was added to facilitate burrowing for larvae and adult beetles. Carrots, wiped with 96% ethanol prior to use, were placed on top of the diet to serve as water source, and were replenished as required during the life cycle, which varied between 12-16 weeks. Wooden culture boxes containing the egg, larva, pupa and beetle stages of MW were placed in a temperature-regulated room at an average temperature of 26°C and at an RH of 55%. Depending on the size of the colony, bran was replenished once every two weeks and carrots were added every week. At least once every three months, or as soon as the diet seemed to become moist, beetles and larvae were separated from eggs and frass, using a sieve of 1200 µm. Fresh diet and carrots were then added to the culture box, containing beetles and larvae. Frass containing the eggs was placed in a separate container, to which fresh diet and carrots were also added, making it available for consumption by the next generation of mealworms. During periods that mealworm and wax moth larvae were not needed in large numbers for experiments, the culture boxes were moved to a 14°C culture room to slow down the developmental rate of the hosts concerned. Conclusion The aim of the culture method used in the current study was to ensure a continuous supply of sufficient numbers of high-quality wax moth larvae and mealworms. The aim was successfully achieved, with the insects concerned being available, in various life stages, throughout the study. Basic equipment was used and the diets selected were also cost-efficient. Although slight contamination problems were experienced in initial mealworm diets, due to the addition of carrots as water source, the problem could be overcome by removing the carrots before rotting or by replacing them with an alternative water source, such as wetted paper towels. Sufficient numbers of mealworms were still produced, even though moderate contamination occurred. However, the prevention of contamination through the implementation of effective sanitary measures is key to a successful
Mealworm adults being placed on top of the diet in wooden boxes. rearing programme. The in vivo production of EPNs for the control of insect pests has been extensively studied. However, enhancing and streamlining each step in the production process could contribute towards creating a more effective, cost-efficient and practical culturing method, specifically customised for EPNs that are endemic to South Africa. Acknowledgements The financial assistance of the South African Apple and Pear Producer's Association (SAAPPA), Citrus Research International (CRI), Technology and Human Resources for Industry Programmes (THRIP) and the National Research Foundation (NRF) towards this research is hereby acknowledged. Note: This article has been adapted from the following source: VAN ZYL, C. 2012. In vivo production of Heterorhabditis spp. M.Sc. thesis, Department of Conservation Ecology and Entomology, Stellenbosch University, 1-99 pp. CONTINUED FROM PAGE 67 co-operation with the Forelle Producers Association (FPA). The correct harvest maturity standards would need to be identified and timeously distributed to all those participating in the programme, and suitable early orchards that meet the delayed harvesting specifications, must be identified and monitored. Although levels of astringency were low in the orchards selected for the 2011 trial, as this disorder is predominantly found in less mature fruit, a few consumers did complain about the fruit being astringent. Future orchards must therefore be selected that do not have a history of astringency. Delaying harvest for 2 to 3 weeks is not without its risks as fruit may experience a slight loss in red blush colour, and may be more prone to abscission in strong winds. For this reason, the orchards intended for short term storage would need to be carefully selected and monitored. A system must be set in place to ensure that only Forelle fruit that have met the above criteria and have been subjected to SmartFreshSM are exported. Suitable target markets and retail partners would need to be identified and there must be a strategy to sell or keep the surplus fruit that do not make the export grade. Dispensation during semicommercial trialing would need to be applied for, and most importantly, there must be continued feedback from retailers and supermarkets regarding consumer acceptance and/or complaints. Reference Crouch, I.J and H. Bergman, 2010. Forelle pears: Post harvest manipulations to enable versatile marketing of good quality fruit. South African Fruit Journal Vol. 9 (4): 35-37. 71 SA VRUGTEJOERNAAL DES/JAN 2013

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