Increasing Marketable Production of Exotic Tropical Fruit with Protective Covering

Final Report for FW02-008

Project Type: Farmer/Rancher
Funds awarded in 2002: $12,850.00
Projected End Date: 12/31/2003
Region: Western
State: Hawaii
Principal Investigator:
Ken Love
Hawaii Tropical Fruit Growers
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Project Information


For hundreds of years throughout most of Asia, farmers have been covering fruit with paper either to
protect their appearance or to increase the time the fruit would be on the tree thus making it sweeter. In
some locations the bags are used for protection from various pests.

Currently there are over 3000 types of bags manufactured in Japan alone. In addition to differences in
size, the bags vary in the amount of light being transmitted to the fruit, color of paper, wax coatings and
chemicals impregnated in the paper. (.05% daiazinon is the most common). The bags all have a small
wire imbedded at the top in order to facilitate the wrapping process. There are slits in the bottom so that
any rainwater can drain out.

The bags we used for this test were made in Niigata Japan where they are used primarily on apples,
asian pears, loquat, peaches, grapes and mango. Bags are used to control ripening time, for desired
coloration and for pest control. The company works directly with growers as well as wholesalers to find
the best bag for a particular crop. The company recommended the types of bags tested after input from
Hawaii growers and a tour of Big Island farms.

Members of the Hawaii Tropical Fruit Growers, West Hawaii chapter,
Kona Pacific Farmers Cooperative and Kona Young Farmers, participated in a number of bagging tests
to determine the time to bag various fruit.

Fruit chosen to test were loquat, White sapote, Mango, Lychee, Figs
and Rambutan. Some collaborators preformed additional tests on abiu, pineapple, strawberry guava,
tomato, zucchini, and eggplant.

Weather patterns had an effect on which fruit were chosen for more
extensive testing. As it was an extremely poor season for mango,
we choose to concentrate more on abiu.

In all cases, we found the bags very effective in pest control.
Other advantages in using the bags were for coloration and
length of time the fruit could stay on the tree which in turn
increased its value because of better coloration and having
the fruit available "off season". Unexpected benefits were drastically reduced -time it takes to inspect and cull.

Using the protective bags also helped to create markets
for fruit which is not usually found in stores as it
is almost always unmarketable due of insect infestation
or bird damage. Loquat, white sapote and abiu are examples
of fruit what show great market potential with the use of the
bags. Marketable Lychee increased dramatically with bag use
as did the value per pound. Benefits with other tropical fruit
are tremendous but more extensive testing is needed to
determine the best types of bags to be used on mango,
figs and guava.

Results of the testing was presented to an International Fruit
Growers' conference held in October of 2002. A display of
bags and results are also put on display each Thursday
at a farmers market held by the Kona Pacific Farmers Cooperative.
Results are also posted on the web site,

We believe that as farmers adopt the use of the protective bags,
the value of their crop will increase both from quality and quantity.
Sales of the bags should help the Kona Pacific Farmers Cooperative
increase equity for their members. Increased availability of the unusual fruit will help with consumer
awareness in developing extended markets
for farmers choosing to greater diversify what they grow.

Use of the bags enables farmers to increase production while
staying chemical and pesticide free in what they grow and bring to market thus promoting good stewardship of the land.


see Summary

Project Objectives:

The objective of this study was to investigate the effects of using protective bags on tropical fruit in order
to increase production and quality as well as to develop new markets for Hawaii. Results were
measured as to both economic impact via market development and the horticultural value of using
protective fruit wrapping as an alternative to chemical treatment.


Materials and methods:

see Outcomes

Research results and discussion:

Various fruit were tested at different levels by a number of collaborators. In some cases the same fruit
was tested by a number of participants and added together in the totals. Results are reported by fruit


Although popular in many countries, the loquat has never found much of a following in Hawaii or the
U.S. market. This in part because of birds and other pests destroying the fruit before it becomes ripe.
Following the horticultural techniques of Japan, we were able to develop a local market for loquat by
using the fruit bags as well as specific pruning styles.
Use of the bags is on going. To date we have used 9000 bags on loquat
covering approximately 17,000 fruit at 3 locations ranging from 800 feet above sea level to 2000 feet.
Types of bags tested:
White with light wax coating and 50% light transmission.
Recycled phone book paper with 33% light transmission.
Inner coated recycled phone book paper with 4% light transmission.

Fruit was bagged after it had been thinned and developed to about 20 cm in length. In some cases top
leaves were stripped back to facilitate the bagging.

We found few differences in bags during the previous years testing other than fruit exposed to direct
morning sunlight would be susceptible to sunburn during the green to yellow stage of fruit development.
When the fruit receives more sunlight, we found that using bags with less light transmission was
desirable for better coloring and no damage. Larger bags (205mm x 300mm) were used to bag 3 or
more fruit in a cluster and bags (102mm x 131 mm) were used for individual fruit.

The use of bags on loquat is common in Japan, China, Spain, Israel, Algeria and other producing
countries. For Hawaii it presents a unique opportunity for a new local market and a future possibility of
export as our harvest time is different from other growing areas around the world.

Unbagged and bagged fruit on the same trees were counted and checked for damage. To date:
9000 bags used
14,380 bagged fruit counted (Approximately 3000 fruit still on tree)
14,336 marketable
44 insect damage
3864 unbagged fruit counted
Bird damage: 1652
Fruit fly stings : 1384
Other: 158
Useable: 670

Since there has been no market for loquat locally, we sent samples to a number of hotels as well as sold
some in local groceries and our coop
farmers market. After a test shipment to one hotel, the chef called to say they would purchase all the
loquat we could supply. Based on these results, we applied for and received a permit to bring in newer
varieties from Japan. These will be in full production within 4 years.


Perhaps the most extensive testing we performed was on lychee. Trees at five locations ranging from
900 to 1600 foot elevations were used. Varieties tested included Kaimana, Pot po hung, Brewster, Groff,
Kwai mi and a number of seedlings.

Preliminary previous years testing dictated that we use open bottom
bags in order to prevent some mealy bug or roach infestation. The white bags available were 254 mm x
340 mm. Based on this years test we would recommend a length of 450 mm and a wire that extended
an additional 30 mm from the top of the bag. In years with a heavy fruit set, the width could be extended
to 300 mm. The additional length would help protect against the fruit fly stings that occurred on the
bottom fruit in bagged clusters. The extra wire would facilitate the bagging process in tightly grouped
clusters and while bagging from a ladder.

The translucent white bags with 50% light transmission helped to promote more even ripening on the
lychee. There were few cases of the side facing the sun being red and the back side still green. With the
bags, we could keep the fruit on the tree up to 3 weeks longer allowing it to ripen to it's fullest and
enabled us to have fruit to sell after the season was over for other growers. The coloration on Kaimana
was perfect and we could command a higher price for the perfect fruit.

We bagged the lychee after the main fruit set. This being a mediocre
year for lychee in Kona, the bags insured a greater number of marketable fruit. In some cases, with
smaller clusters of fruit that were next to each other, we stripped some of the leaves and bagged 2 of the
clusters together. With a longer bag, this leaf stripping might not be necessary.

We found some differences between the varieties bagged although most of our efforts went into
Kaimana. With Pot po hung, there were greater incidents of mealy bugs than on other cultivars. The
Brewster seemed more resistant to stings and birds.

In some cases the crop from whole trees was bagged while other trees were left unbagged. In other
cases trees were left half unbagged. We could tell no difference in percentages of good fruit versus
damaged fruit. Of high number of stings or infestation on bagged fruit,1004 cases, 998 occurred on the
fruit at the bottom of the bags.

With labor, we found it easier to find part time help at the time of bagging
for $10 to $12 per hour than during harvest time at $12 to $15 per hour.

One of the biggest differences we found was in the time to cull harvested fruit. The average time to
harvest and prepare an order was less than half with the bagged fruit. Overall we are looking forward to
next season when we don't have to count all the fruit!

Lychee numbers

Bagged fruit
total harvest 5997
marketable fruit 4768
damaged fruit 1229
split 60
bird 9
sting or infestation 1004
immature 159

unbagged fruit
total harvest 10,739
marketable fruit 4379
damaged fruit 6360
split 1 14
bird 2373
sting or infestation 1825
immature 2048


Average time to bag fruit = 7 minutes for 25 bags
Average number of fruit in bag: 23
Average number of fruit per pound: 25

Average time to harvest
75 fruit = 9 minutes - unbagged
75 fruit = 8 minutes - bagged

Average time to cull fruit
2163 fruit in 219 minutes - unbagged
238 bagged fruit - 7 minutes to unbag and cull

external labor cost
Average cost per hour for pre season labor $1 0. to $1 2.
Average cost per hour for peak season labor $12. to $15.

We believe that the increase in labor cost and the cost of the bag is more than offset by the greater
number of fruit that is marketable and by the
time saved during the culling process.

Per 1000 Lychee
Bagged = 32 pounds at an average price of $3.50 per pound.
Unbagged =16 pounds at an average price of $2.75 per pound.

Overall labor time was less with the bags because of the
dramatic decrease in time to cull harvested fruit.
Per 1000 lychee we could achieve an additional profit of $75.00.
This translates to an increased farmer income of $3750.00 per acre of lychee each year using the
protective bags.


Thought to be the first fruit wrapped in Hawaii, the practice of protecting figs from bird and insect
damage was lost as itinerate labor moved on to steady jobs in the pineapple and sugar fields of the

We tested 5 fig trees in 3 locations from 600 foot to 1300 foot elevations. In previous years, in order to
protect fruit from birds and fruit flies, we strung a number of cd roms from branches, hung aluminum foil
and Christmas tinsel as well as left a half dozen fruit fly traps around the tree. The main tree for this test
is at the 1300 foot elevation in South Kona. This brown turkey variety produced an average of 250 figs
per year for approximately 15 years. From that, only a handful ripened fully and were without damage
and edible. None were what I would call sellable. In an effort to secure a sellable crop, we started to use
the cd roms to scare birds in 1998. In 1999 we added the fruit fly traps, more cd's and tinsel. This being
an exceptionally good year for figs, we were able to harvest 268 that were in perfect condition, out of previous harvest sc
- In, we had 230 perfect figs out of 281. In
- 01 we used 200 bags, 180 of which
produced sellable fruit. Damage to the other 20 figs was caused by insects on over ripe fruit that we did
not harvest in time. This was true of fruit on the other trees we tested. Perhaps because of the additional
heat inside the bag, the fruit tends to ripen much faster. In some cases with bags with less light
transmission, the brown turkey figs, will stay green but ripen and become soft and sweet to the taste.
Kadota figs also ripened faster inside the bags and have a light green color when ripe.

From the first 100 bagged figs,
undamaged fruit 94
damaged 6

The damqged fruit was caused by what I believe were rats eating through the paper. This occurred on
both uncoated and wax coated bags.

unbagged figs
86 were damaged from birds.
It was impossible to tell if the fruit was stung as the birds would leave only a small piece of skin or the
stem of the fruit.

There are 300 bags currently on the fig trees and we should be testing close to 1000 figs in total this year.

We used 3 types of bags, all of which had a V cut in the top center of the bag to facilitate bagging the
fruit close to the branch. In some cases we
would remove leaves close to the fruit. Bagging takes place when the fruit is developed to about 30cm in

Types of bags tested:
Red with light wax coating and 38% light transmission.
Light brown with wax coatiqg and 61 % light transmission.
Recycled phone book paper with 33% light transmission.

We also plan to test large white bags over the stems where 3 or 4 figs are clustered.

Fresh figs also represent a potential market. We've received a number of calls from wholesalers, hotels
and West Coast distributors asking for quantities. Currently we sell some fresh figs in the local grocery
and farmers market but most of them are processed into jam for two local shops and a shop in Japan.


The growing popularity of this fruit in local and mainland markets warrants growers giving it much more
space in their fields. Currently
with 5 prolific producing trees we cannot supply enough for 1 customer. The attractive yellow color
makes it a target for consumers as well as for birds, fruit flies and hosts of other pests. With an
approved treatment for irradiation, the abiu has a promising future for Hawaiian growers. In our test
marketing at the Kona Pacific Farmers Cooperative (KPFC), we've had no negative comments on the

We bagged abiu at locations ranging from 900 to 1500 ft.
elevations. Previous testing taught
us that bags with a V cut in the center top and an extended wire, cut bagging time considerably. When
we bagged fruit in previous years, we found some green fruit with and apparent fruit fly stings and some
with a sunburn. This year we bagged younger fruit, about 6cm in length. In some cases, perhaps
because of our dryer area, rough handling during the bagging caused the fruit to fall from the branch.
Greater care and more time had to be taken with individual fruit. In other cases, fruiting and flowering
occurred at the same time and flowers close to the fruit were removed during the bagging.

This year we are using a light brown bag with wax coating and 61% light transmission.

From the bagged 5000 fruit, only 38 had insect damage or visible imperfections. In these cases mealy
bugs or roaches nested inside
the bags. From 150 unbagged fruit, all had damage that would
prevent it's being sold. Both bird and fruit fly stings were evident on the unbagged fruit.

In previous years, we have been able to get few fruit to market that had not been bagged. Our
conclusion is that bagging abiu is the only way to make it marketable in West Hawaii.

White Sapote

A fruit that thrives at higher elevations in Kona, the sensitivity of the skin as well as the fruit seems to
prevent successful marketing. However, at the KPFC test market, those trying the fruit for the first time
have always asked for seconds or purchased a number of the fruit. The tree also has a reputation for
abortirlg small fruit and dropping others in strong winds. We looked at bagging the fruit as a way to keep
the fruit attached to the tree with the help of the wire in the bag. This practice is common for greenhouse
grown mango in Japan. Pest control and even coloration were also helped by bagging. The white sapote
that seems to suffer from a number of viruses as well as insect damage and we found the bags seemed
to promote consistency in ripe fruit.

Types of bags tested:
Red with light wax coating and 38% light transmission.
Light brown with wax coating and 61% light transmission.
Recycled phone book paper with 33% light transmission.
White with light wax coating and 73% light transmission.

Although there were some differences in fruit color with the various bags, we could discern no other
differences with the limited testing.

200 bags were used on trees in 4 locations. In a few cases the fruit did fall inside the bag and various
beetles would chew through the bag to get at the fruit. All the bags that fell had some infestation. From
the 184 fruit harvested, the color was more even and the skin undamaged. Fruit that was bagged at a
later stage of development still had some skin discoloration but this did not affect the flesh or taste of the
fruit. There was no insect damage in any of the bagged fruit.

Out of 184 unbagged fruit randomly chosen for comparison, 103 had some insect damage that would
make the fruit unmarketable. In 32 cases, the fruit had split which made it more appealing to other insects.
White sapote will ripen after harvest and the use of the bags
along with taste tests at the KPFC test
market showed that there is a potential for this fruit in today's marketplace.


Although a poor season for mango in Kona, we were able to perform a few tests on the varieties:
Kensington, Kurashige, Pirie, Peach and an unnamed Australian variety. Mangos are being bagged
successfully in Japan and other Asian growing locations but it is unclear if these locations have the
same problems with fruit fly, seed weevils, mites, thrips, anthracnose a n d s t e m rot and the other
problems that plague Hawaiian growers. Closed bottom bags are used in Japan where mangos are
grown inside green houses and on the Ogasawara islands.

We tested both closed and open bottom bags in a variety of colors and light transmission capabilities.
Although coloring is affected slightly, we could find not significant difference in bags with 33% to 73%
light transmission. More research is indicated in order to determine the best coloration for individual

We found that with open bottom bags some mango were free of infestation. With all closed bottom bags
there was some infestation
from either roaches or borers. In some cases cane spiders or geckos
made a home inside the bags. For some reason this only happened
on mango.

The trees we tested were at 800 and 900 foot elevations. With these limited tests of only 120 bagged
fruit, the only notable difference was on the Kensington. The bags seem to promote a more even
coloring and were more blemish free than the unbagged fruit. 'There were no stings on the bagged fruit
whereas all the unbagged fruit had some sting damage.

Fifty bagged Kensington were marketable.
Fifty unbagged fruit, were not marketable but 20 were edible and
good for home use or for processed products.

The 25 bagged Kurashige seemed to suffer from stem rot, anthracnose or thrips both in and out of the
bag although this could be because of the time at which we bagged the fruit.

The Australian variety had a much lighter coloration when bagged
than the unbagged fruit even with 73% light transmission. Coloring
was uneven in both bagged and unbagged fruit. The 20 bagged mango
were free from infestations with the exception of roaches on both
open and closed bottom bags. Unbagged fruit fell from the tree much faster than the bagged fruit
although the bagged fruit seemed to ripen faster.

Our conclusion is that much more research is needed to determine the types bags to use for different
mango varieties and the best time to bag them.

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

Based on both the weekly display at the Kona Pacific farmers Cooperative Farmers market and a
presentation at the International Hawaii Tropical Fruit Growers conference in October 2002, a number of
local and
other island growers have inquired about bag purchase. A number of orders have been received and
shipment requested from Japan.

The display on the bags continues weekly and new farmers are given
samples. Some farmers desire the bags for home use on tomato
and cucumber which are almost always victims of fruit fly.
It is a slow process as many are reluctant to buy bags when they
are unsure of the results themselves. The WSARE grant has enabled
us to give lots of 100 bags to many farmers for their own testing
and this has helped greatly to spread the word.

Education and Outreach Outcomes

Recommendations for education and outreach:

Potential Contributions

Although many farmers are slow to adopt change, the protective
fruit wrapping is appealing for a number of reasons. The economic
impact for small farmers is easily measurable after a year of tests.
Time saved in the culling process for various fruit outweighs the
time taken to bag the fruit. The difference in quality is very
visible as well as marketable. lmpact or more correctly, potential
or future impact can be multi-faceted. Greater income for the farmer
based in marketing of the quality as well as increased quantity.
Use of the bags eliminates the need for pesticides or other
chemical applications. The protective wrapping on some fruit
such as loquat which had not been marketed before can now be
sold. The bags can also help to increase a farmer's ability to be classed
as organic.

Future Recommendations

With over 3000 types of bags being made, further testing would
be indicated in order to find the optimum bag for each specific
tropical fruit as well as by variety. Publicity for the bags
in agricultural publications would also be useful in showing
farmers the advantage of their use. This combined with published
testimonials from chefs and fruit buyers as to the increased quality
would also help insure wider adoption of bag use.

A presentation at the International Hawaii Tropical Fruit Growers conference held in October 2002 was
the first introduction of results
obtained from this project. Attendees from South East Asia
to Florida were able to view and take samples the bags. This presentation
is available on Internet.

The weekly display at the Coop farmers market enables both local people
and visitors to see the bags and results obtained. Bagged and unbagged
fruit is often available. Growers who have heard about the bags often
come to the market in order to learn more and see the catalogs from
the manufacturer.

Through the website,
http://www. mycoffee.net1fruitindex.htmI
all reports and many more photos are available.

We have been asked to present information on the
bag use at a conference in Indonesia in August of 2003.
If funding is not available, representatives of the bag
manufacturer will present information and provide samples
to attendees.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.