Fruit Tree Overview
Fruit Tree Bloom Times
There is an order to the blossoming of fruit trees.
This has important implications in the Northeast. Earlier blooms can be killed by frosts resulting in no fruit for that year. For example, you will rarely get Apricots to fruit but have little trouble getting pears and apples from your trees.
There is an order to the blossoming of fruit trees.
- Apricots are the first to bloom (at the same time as forsythia and magnolias, mid to late April)
- Then sweet cherries and peaches
- Followed by plums
- Next are pears and tart cherries
- Finally, apples
This has important implications in the Northeast. Earlier blooms can be killed by frosts resulting in no fruit for that year. For example, you will rarely get Apricots to fruit but have little trouble getting pears and apples from your trees.
Types of Fruit Trees
We have tried many types of fruit trees focusing on disease-resistant varieties when available.
These are what we currently grow successfully:
Apples
Asian Pears
European Pears
Paw Paws
Persimmons (will be planted in 2020)
Plums
These are ones we tried then rejected:
Apricot - would not fruit reliably. Apricots are even more sensitive to Spring frosts than plums.
Black Cherry - birds eat them all just before they ripen.
Fig - dies back to ground level over winter, regrows, but not enough time for fruit to ripen. Near the Connecticut coastline, in a warmer hardiness zone, some people dig and bury the tree for the winter, then dig it out in the spring and successfully grow figs in Connecticut.
Mulberry - beautiful healthy tree but grows too fast and tall for our site - blocking the sun. Taste of the fruit is okay but not great. However, if the tree is kept short, it only yields a handful of fruit and is not worth the effort.
Peaches - Tried several varieties but all get the fungal disease 'Brown Rot' just before ripening. Also, plastic bags do not work with peaches - again because of Brown Rot. The amount of good fruit salvaged is not worth the time spent. Peach trees that I have rejected and pulled out due to Brown Rot are: Glo Haven, Hale Haven, Harrow Diamond, Red Haven, Saturn, White Lady. Also, Elberta Peach, supposed zoned for 5-9, died over the 2014-2015 winter on our zone 6a site. If you know of a peach variety that will survive Brown Rot in Connecticut without sprays, please Contact me and let me know the name of the variety and your experience with it.
Trees pruned to no higher than 8 feet
I prune all our fruit trees to be less than 8' high, so I do not need to climb ladders. Even standard trees that grow 30' high can be pruned to 8' if you know the secrets. Read this book on how to do it. "Grow a Little Fruit Tree: Simple Pruning Techniques for Small-Space, Easy-Harvest Fruit Trees"
How many years till you get fruit?
This varies wildly depending on whether the tree it is self-rooted or grafted - if grafted, what rootstock it was grafted onto.
To be true to type, a cutting from the original variety is either self-rooted or grafted onto a rootstock. Different rootstocks have different properties of disease-resistance, years till fruit, vigor, and ultimate size of the tree if untrained. If grown from seed, it is a throw of the dice what comes out so this is not a normal method of propagation unless you are a breeder attempting to discover new varieties.
Generally self-rooted and some rootstocks (like some in the M series) take 5 to 10 years to fruit, while other rootstocks (like Geneva) take 1-3 years to fruit. Also, some rootstocks give disease resistant properties to the tree while others do not. For example, Geneva root stock is fireblight resistant while many in the M-series are not.
So, when did our trees bear fruit?
We have had some fruit trees fruit in their second year, while two semi-dwarf apple trees, on M-series rootstock, planted in 2010 still have no fruit. Others are in between. So far, the only heavy bearers are 'Kieffer' and Asian pears. Our one apple tree that was a heavy bearer ('Liberty') was killed by the Gypsy moth invasion of 2016-2017. All peach trees were heavy bearers with vigorous growth but their fruit would mostly rot from Brown Rot fungus so, I removed them . Plum trees were heavy bearers, but most years frost killed the buds, so I pulled out these Asian plums and in 2020 am replacing them with cold-hardy hybrid crosses (American x Asian).
Regarding longevity, standard apple and pear trees live 35-40 years, while dwarf trees of the same type live just 15 to 20 years. So there is a trade off here.
So, depending on what you want, choose your rootstock carefully. The little bit of time spent in selecting the right rootstock saves you years of going down dead ends in the garden. Be aware that It often takes a lot of shopping before, or even if, you can find what you want. Do your online shopping in the early Fall. If you wait till late winter, many varieties are sold out. Bare root fruit trees are shipped for Spring planting.
Most of the fruit trees that have died in our orchard were ones on rootstocks not resistant to fireblight and scab. So, in the Northeast, these are two properties that is critical for any fruit tree you plant. So, pick your varieties and rootstocks with a fair amount of research and thought.
For information on the properties of specific rootstocks, do an Internet search.
A good place to start for apple and pear rootstocks is Washington State University.
Starting places for stone fruit (plums, peaches, cherries) rootstocks are Dave William's Nursery and Orange Pippin.
Bare Root
It is best to buy Bare Root fruit trees and plant in the Spring in colder areas like ours. These arrive looking like sticks with roots. Buy at a reputable online nursery so you do not get taken by some fly-by-night selling you dead sticks. At $8 to $30 each, this is your least expensive way to go and they produce wonderful trees. Another way is to buy live trees in pots, however, that is expensive and can cost $75 to $190 each. Follow the tree planting directions provided by the nursery and that book mentioned above.
Why so many?
I have planted many varieties of fruit trees, so you may ask, why so many?
There are several reasons. First, is for the shear enjoyment of experiencing these fruit, berries, flowers, and vegetables as they grow. Second, I keep all fruit trees small - under 8' in height. I do not want to climb ladders and smaller trees are easier to manage. The yield will be much lower on a short tree than a full-sized tree. Third, it is impossible for me to foresee which varieties will do best in our yard. It can take up to ten years for some variety/rootstock combinations to fruit. So, if I planted one tree, then 10 years later I discover it is not doing well or we do not like it, ten years have just been wasted. So, my strategy is to plant multiple varieties, then, over time weed out those that do not do well.
Already, we have lost some fruit trees. A few died for unknown reasons, a few died from the Gypsy moth invasion of 2016-2017, while others had poor flavor and were removed.
When we began, we knew little about gardening, and unknowingly I bought trees with rootstocks that were susceptible to disease, or fruits that were affected by New England's capricious late frosts. We learned from this and now select better variety/rootstock combinations.
Wild Insects
There are millions of insect species in the world with over 100,000 in the USA. Of these, 99% are beneficial. In the garden, these beneficial insects feed on pest insects, pollinate crops, and break down organic matter to improve soil. Let me mention just a few.
Three-fourths of the world’s flowering plants and 35 percent of the world’s food crops depend on insect pollinators.
To attract beneficial insects to your garden, plant a diversity of crops and flowers and avoid using insecticides. If some species of insects are not present, you can buy them and introduce them to your garden. They will stay if they find plants they like. The best way, however, is to grow wildflowers. A good source is Prairie Moon Nursery. They have seed mixtures of wildflowers. The two best for gardeners are "INSECTOPIA" for predatory beneficials and "POLLINATOR-PALOOZA" for pollinators.
Syrphid flies (aka Hover flies), which resemble small wasps but do not sting, are not only great pollinators, but their larvae eat aphids, cabbage worms, caterpillars, and mealybug.
Parasitic Wasps prey upon on insect pests. These tiny, non-stinging wasps are some of the most beneficial insects in the garden, and a great partner to the gardener and farmer. These are the pests they kill: aphids, beetle larvae, bag-worms, cabbage worms, Colorado potato beetle, corn ear worms, cucumber beetles, cutworms, gypsy moth caterpillars, Japanese beetles, leaf-miners, mealybugs, Mexican bean beetles, moth caterpillars, sawfly larvae, scale, squash vine borers, tent caterpillars, tobacco bud-worm, tomato horn-worm, and white flies.
A few other common beneficial insects that feed on the harmful bugs are: Assassin Bug, Big-Eyed Bug, Damsel Bug, Earwig, Green Lacewing, Ground Beetle, Lady Bug, Minute Pirate Bug, Praying Mantis, Predatory Stink Bug, Tachinid flies, etc.
Bees and other insects are needed to pollinate many of your fruits and veggies. Honeybees are well know for this, but there are many others.
Some fruits, like plums, flower a little too early, when it’s a little too cold, when it rains too much, and the nectar is not quite sweet enough for the fussy honeybee's tastes.
Enter the wild bees, specifically the Mason bees and tiny wasps. Mason bees are active only in the Spring and pollinate fruits and berries.
Mason bees are non-aggressive and pose no threat. Half of them do not even have stingers, and those that do, the stinger is too tiny to be worrisome. But by early June Mason Bees die off.
Unlike honeybees that travel for miles, mason bees travel no more than 100 yards from their birthplace - provided there are enough plants in bloom to keep them happy, plus housing and mud to make babies for next year.
After the Mason Bees die off, next to arrive on the scene are the leafcutter, sunflower, squash, honey, and bumble bees, the hover flies, and wasps and hornets to pollinate your late Spring and Summer crops.
Three-fourths of the world’s flowering plants and 35 percent of the world’s food crops depend on insect pollinators.
To attract beneficial insects to your garden, plant a diversity of crops and flowers and avoid using insecticides. If some species of insects are not present, you can buy them and introduce them to your garden. They will stay if they find plants they like. The best way, however, is to grow wildflowers. A good source is Prairie Moon Nursery. They have seed mixtures of wildflowers. The two best for gardeners are "INSECTOPIA" for predatory beneficials and "POLLINATOR-PALOOZA" for pollinators.
Syrphid flies (aka Hover flies), which resemble small wasps but do not sting, are not only great pollinators, but their larvae eat aphids, cabbage worms, caterpillars, and mealybug.
Parasitic Wasps prey upon on insect pests. These tiny, non-stinging wasps are some of the most beneficial insects in the garden, and a great partner to the gardener and farmer. These are the pests they kill: aphids, beetle larvae, bag-worms, cabbage worms, Colorado potato beetle, corn ear worms, cucumber beetles, cutworms, gypsy moth caterpillars, Japanese beetles, leaf-miners, mealybugs, Mexican bean beetles, moth caterpillars, sawfly larvae, scale, squash vine borers, tent caterpillars, tobacco bud-worm, tomato horn-worm, and white flies.
A few other common beneficial insects that feed on the harmful bugs are: Assassin Bug, Big-Eyed Bug, Damsel Bug, Earwig, Green Lacewing, Ground Beetle, Lady Bug, Minute Pirate Bug, Praying Mantis, Predatory Stink Bug, Tachinid flies, etc.
Bees and other insects are needed to pollinate many of your fruits and veggies. Honeybees are well know for this, but there are many others.
Some fruits, like plums, flower a little too early, when it’s a little too cold, when it rains too much, and the nectar is not quite sweet enough for the fussy honeybee's tastes.
Enter the wild bees, specifically the Mason bees and tiny wasps. Mason bees are active only in the Spring and pollinate fruits and berries.
Mason bees are non-aggressive and pose no threat. Half of them do not even have stingers, and those that do, the stinger is too tiny to be worrisome. But by early June Mason Bees die off.
Unlike honeybees that travel for miles, mason bees travel no more than 100 yards from their birthplace - provided there are enough plants in bloom to keep them happy, plus housing and mud to make babies for next year.
After the Mason Bees die off, next to arrive on the scene are the leafcutter, sunflower, squash, honey, and bumble bees, the hover flies, and wasps and hornets to pollinate your late Spring and Summer crops.
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Protected Housing
To help the Mason, Leafcutter, and Sunflower bees, provide them with protection, blossoms, clean housing, moist mud, and leaves.
Birds eat insects. I have found Mason Bee tubes all over the ground, pulled out of the enclosure and saw a woodpecker feeding on a mason bee house. As shown in the photos, a solution is to cover the front of the mason bee house with 1/2" hardware cloth.
You can buy ready-made mason bee houses or, if you are handy, make your own with 6" tubes or drill 6" deep holes into pieces of wood (not cedar which naturally repels insects). Mason Bees prefer holes 5/16" in diameter, while Leafcutter Bees prefer 3/16". Also provide a few holes slightly larger and smaller than these since one size does not fit all.
The homes do need to be cleaned out annually to prevent a buildup of pollen mites. Drill out the holes, or replace tube inserts, or drill new logs each year. If left to sit for 3 or 4 years, the pollen mite numbers will increase to the point where they will kill all the bee larvae.
These houses need to be in place for mid to late April, so the Mason bees can lay their eggs for next year in May. The houses should be placed where they are protected from rain by an overhang and several feet off the ground. Also, make sure moist mud is present. Mud is used to pack their eggs for next year. Mason Bees will not lay eggs unless mud is available near the nests. Leafcutters will find enough leaves on their own to pack their nests, but they emerge and lay their eggs later in the season. Leafcutter bees emerge in June and pollinate the late spring and summer crops.
Protecting Fruit from Disease and Insects
Fruit without Pesticides
According to the Environmental Work Group, apples contain more pesticides that most other fruits.
And fruits in general contain a lot of pesticides.
Some say, "You can’t grow apples and pears without lots of pesticides” …I say, nonsense!!
If you select disease resistant trees and enclosed each fruit in a plastic bag for the season, you eliminate airborne and insect borne diseases and there is no need for pesticides.
“But commercially I cannot bag fruit .” Well, keep in mind that the Japanese do and so do some West Coast organic producers. If they can do it, so can you.
The bags work well on apples, Asian pears, and European pears. I have been bagging our apples and pears for several years, and produce picture perfect fruit with no pesticides, no fungicides, and no herbicides. See the photos of our apples and pears.
On peaches plastic bags encourage rot, so bags are not useful.
On initial tries, bags also do not work on plums because the stem is too short, and it is difficult to use a twist tie without the plum detaching from the tree. However, I have recently learned of exclusion sleeves made of netting that will slide over a plum branch to protect all plums on that branch. Also, the edges of a bag could be extended over the plum and the branch and tied above the branch. Green Harvest of Australia offers a full array of products to protect fruit trees. Their website is quite interesting. Unfortunately, Green Harvest does not ship outside of Australia and I have found no equivalent American company, as yet.
Here is my procedure: Right after petal drop, I spray with "SurroundWP" - a non-toxic kaolin clay. This white powder is mixed in water and sprayed with a backpack sprayer specifically designed for wettable powders. I repeat this spray after each rain until mid-June. Then I thin and bag each fruit with bags and twist ties.
The SurroundWP discourages the Plum Curculio from laying eggs in the fruit. It reduces infection rates from 95% to about 10% in your crop. Then when I thin, I remove infected fruit as part of the thinning process and bag the remaining good fruit - which is about the size of a cherry at this point. Infected fruit is easy to spot. There is a half-moon crescent cut in the fruit where the eggs were deposited. From this point forward, no further spraying with SurroundWP is needed and the fruit stays bagged until harvest.
I have also read anecdotal evidence of planting garlic near fruit trees since Plum Curculio supposedly do not like the smell of garlic. I will need to try this as an added measure since some years it rains more than others and the fruit is unprotected during and after these rains.
Here’s where I buy my 7”x 9” polyethylene bags - cost $23 per thousand, PaperMart
Here are the twist ties - cost $4 per 2,000, PaperMart
Besides plastic bags, farmers have used Organza bags and soft-fabric bags. In Japan, soft-fabric bags are used on a commercial scale to protect their fruit crops. I plan to experiment with both these types bags in 2020 to see which give the best results.
References:
According to the Environmental Work Group, apples contain more pesticides that most other fruits.
And fruits in general contain a lot of pesticides.
Some say, "You can’t grow apples and pears without lots of pesticides” …I say, nonsense!!
If you select disease resistant trees and enclosed each fruit in a plastic bag for the season, you eliminate airborne and insect borne diseases and there is no need for pesticides.
“But commercially I cannot bag fruit .” Well, keep in mind that the Japanese do and so do some West Coast organic producers. If they can do it, so can you.
The bags work well on apples, Asian pears, and European pears. I have been bagging our apples and pears for several years, and produce picture perfect fruit with no pesticides, no fungicides, and no herbicides. See the photos of our apples and pears.
On peaches plastic bags encourage rot, so bags are not useful.
On initial tries, bags also do not work on plums because the stem is too short, and it is difficult to use a twist tie without the plum detaching from the tree. However, I have recently learned of exclusion sleeves made of netting that will slide over a plum branch to protect all plums on that branch. Also, the edges of a bag could be extended over the plum and the branch and tied above the branch. Green Harvest of Australia offers a full array of products to protect fruit trees. Their website is quite interesting. Unfortunately, Green Harvest does not ship outside of Australia and I have found no equivalent American company, as yet.
Here is my procedure: Right after petal drop, I spray with "SurroundWP" - a non-toxic kaolin clay. This white powder is mixed in water and sprayed with a backpack sprayer specifically designed for wettable powders. I repeat this spray after each rain until mid-June. Then I thin and bag each fruit with bags and twist ties.
The SurroundWP discourages the Plum Curculio from laying eggs in the fruit. It reduces infection rates from 95% to about 10% in your crop. Then when I thin, I remove infected fruit as part of the thinning process and bag the remaining good fruit - which is about the size of a cherry at this point. Infected fruit is easy to spot. There is a half-moon crescent cut in the fruit where the eggs were deposited. From this point forward, no further spraying with SurroundWP is needed and the fruit stays bagged until harvest.
I have also read anecdotal evidence of planting garlic near fruit trees since Plum Curculio supposedly do not like the smell of garlic. I will need to try this as an added measure since some years it rains more than others and the fruit is unprotected during and after these rains.
Here’s where I buy my 7”x 9” polyethylene bags - cost $23 per thousand, PaperMart
Here are the twist ties - cost $4 per 2,000, PaperMart
Besides plastic bags, farmers have used Organza bags and soft-fabric bags. In Japan, soft-fabric bags are used on a commercial scale to protect their fruit crops. I plan to experiment with both these types bags in 2020 to see which give the best results.
References:
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This shows how an apple has grown after sitting in a plastic bag for two months. I place slits in each of the bottom two corners of the bag so rain water can drain.
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In 2020, I am going to try some Organza bags to see how they compare with plastic bags for insect and disease prevention.
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Fabric Bags are used commercially in Japan to protect fruit from disease and insects.
These are available on Amazon.
The goals of experimenting with various bags is to find the least expensive bag that will best protect against diseases, insects and birds and yet not interfere with fruit ripening.
Our fencing system keeps out deer, opossum, rabbits, raccoons, and woodchucks, but not birds, chipmunks, squirrels, insects, or disease.
Netting helps with birds, fences help with other critters, but not all areas can be netted or fenced, like on the grape arbor.
Except on the nut trees, I have not had enough trouble with squirrels and chipmunks to worry about, so these can be ignored.
I already know that plastic bags work great on apples and pears. Unlike on grapes, the Asian Fruit Fly (SWD) doesn't appear to bother apple and pears. The only drawback to the plastic bags, with twist-ties, is it is quite time consuming, if you are bagging hundreds of fruits. The drawstrings on the Organza bags would cut down bagging time considerably, but insect may just lay their eggs through the netting, and disease can easily settle on the fruit through the netting. This hypothesis needs to be tested.
I have also discovered from experience, that plastic clamshells do stop raccoons and birds on the grape arbor, but clamshells do not stop wasps or Asian Fruit Flies (SWD). When fitting the portion of a vine, holding a grape bunch, into the plastic clamshell, part of the plastic needs to be cut away to seat the vine. What is needed is to devise a way to seal the entry and exit points of the vine. Even a tiny space will allow entry of the SWD. To close the gaps, one would need putty, or glue, or sealant that would not harm the grapes. I prefer something non-toxic. If you have any ideas on what might work for this, please let me know by emailing me through the Contact section of this website. The first thing I am going to try is a non-toxic, non-drying, modeling clay made with wax and oil. I will need to see if it washes away during rains or sags during hot weather. A glue gun would work great, but that would likely kill that grape cane. Also, I will try stuffing the gap with some cloth or netting.
So far, I have experimented with the inexpensive paper bags, plastic bags and clamshells. I am hoping to find sources where the other bags could be purchased in larger quantities and at better prices.
In 2020, I will test the other types of bags shown above. Surprisingly, paper bags hold up quite well for the entire season, despite our frequent rains. They do not stop raccoons, but they do stop birds, and most insects. The raccoons just rip open the paper bags and eat the grapes. In 2020, I need to observe whether paper bags stop the Asian fruit fly (SWD), and whether they affect fruit ripening. Paper bags could be used in the fenced areas where raccoons are excluded, if the paper bags do not hinder ripening or cause rotting of the grapes.
Plastic bags worked well for many years, and still do, on apples and pears, but the arrival of the SWD, showed their weakness on grapes. The SWD crawl into the slits placed along the two bottom corners of the bags covering grapes, and I observed grapes infected with their larvae. These slits are necessary to allow rainwater to escape. Otherwise. the bags fill up with water like balloons.
I observed something else, plastic bags on grapes appear to delay ripening of many grape cultivars by about one month, but they do protect the grapes from some diseases. On two cultivars, plastic bags quadrupled the size of the grapes (Concord Seedless and Somerset Seedless). This was an unexpected finding. For other varieties, the berries did very well in plastic bags (Jubilee of Swenson, L’ Acadie Blanc, Marechal Foch, Oberlin Noir, Petite Pearl, Solaris, Somerset Seedless, Steuben, Wine King, Worden). On still others they rotted the grapes and/or caused botrytis (Frontenac, Jukka, St Vincent). However, the issue with plastic bags is the SWD, who get inside the plastic bags through the drainage slits on the bottom of the bags.
The vented clamshells protected the grapes on the arbor from raccoons. So far, the raccoons have not figured out how to open these. Wasps, however, enter through the vents, and feast on the grapes. Next, in 2020, I will try clamshells without vents as shown in the photo, but I need to figure out some way to seal them from the SWD.
The fabric bags, Organza bags, and net bags look promising.
The drawstring and flexible fabric, make the organza bags the quickest to tie around the fruit, saving a lot of time. Whether the insects and disease will do damage through the holes in the netting remains to be seen.
The net bags are sturdier and more durable than the Organza bags, but more difficult to get a good seal, due to the stiffness of the fabric. The drawstrings cannot close the top opening completely. This sealing issue may not sufficiently exclude the SWD.
The fabric bags appear to be very good. These are used commercially in Japan. I do not think insects will be able to eat or lay eggs thru this fabric, as they might with the Organza and net bags. Also, they should exclude disease - maybe. The green fabric bags are thicker than the white ones, meaning birds and squirrels will have a tougher time getting to the fruit. Also, the white ones have a thin twist tie vs. a thick sturdy twist tie on the green bags. However, with thinner fabric, when bunched at the top, the white bags yields a better seal, making it less likely the SWD will gain access. On balance, the white bags appear superior. This needs to evaluated by testing in 2020.
Observations in 2020, should tell the tale and reveal which are best suited for the job. My initial guess is the unvented plastic clamshell will work best on the grape arbor against raccoons, if modeling clay can maintain a good seal against the SWD. In the fenced areas, the white fabric bag may work best.
The biggest scourge to overcome is the tiny Asian Fruit Fly (SWD) on grapes and berries.
Our fencing system keeps out deer, opossum, rabbits, raccoons, and woodchucks, but not birds, chipmunks, squirrels, insects, or disease.
Netting helps with birds, fences help with other critters, but not all areas can be netted or fenced, like on the grape arbor.
Except on the nut trees, I have not had enough trouble with squirrels and chipmunks to worry about, so these can be ignored.
I already know that plastic bags work great on apples and pears. Unlike on grapes, the Asian Fruit Fly (SWD) doesn't appear to bother apple and pears. The only drawback to the plastic bags, with twist-ties, is it is quite time consuming, if you are bagging hundreds of fruits. The drawstrings on the Organza bags would cut down bagging time considerably, but insect may just lay their eggs through the netting, and disease can easily settle on the fruit through the netting. This hypothesis needs to be tested.
I have also discovered from experience, that plastic clamshells do stop raccoons and birds on the grape arbor, but clamshells do not stop wasps or Asian Fruit Flies (SWD). When fitting the portion of a vine, holding a grape bunch, into the plastic clamshell, part of the plastic needs to be cut away to seat the vine. What is needed is to devise a way to seal the entry and exit points of the vine. Even a tiny space will allow entry of the SWD. To close the gaps, one would need putty, or glue, or sealant that would not harm the grapes. I prefer something non-toxic. If you have any ideas on what might work for this, please let me know by emailing me through the Contact section of this website. The first thing I am going to try is a non-toxic, non-drying, modeling clay made with wax and oil. I will need to see if it washes away during rains or sags during hot weather. A glue gun would work great, but that would likely kill that grape cane. Also, I will try stuffing the gap with some cloth or netting.
So far, I have experimented with the inexpensive paper bags, plastic bags and clamshells. I am hoping to find sources where the other bags could be purchased in larger quantities and at better prices.
In 2020, I will test the other types of bags shown above. Surprisingly, paper bags hold up quite well for the entire season, despite our frequent rains. They do not stop raccoons, but they do stop birds, and most insects. The raccoons just rip open the paper bags and eat the grapes. In 2020, I need to observe whether paper bags stop the Asian fruit fly (SWD), and whether they affect fruit ripening. Paper bags could be used in the fenced areas where raccoons are excluded, if the paper bags do not hinder ripening or cause rotting of the grapes.
Plastic bags worked well for many years, and still do, on apples and pears, but the arrival of the SWD, showed their weakness on grapes. The SWD crawl into the slits placed along the two bottom corners of the bags covering grapes, and I observed grapes infected with their larvae. These slits are necessary to allow rainwater to escape. Otherwise. the bags fill up with water like balloons.
I observed something else, plastic bags on grapes appear to delay ripening of many grape cultivars by about one month, but they do protect the grapes from some diseases. On two cultivars, plastic bags quadrupled the size of the grapes (Concord Seedless and Somerset Seedless). This was an unexpected finding. For other varieties, the berries did very well in plastic bags (Jubilee of Swenson, L’ Acadie Blanc, Marechal Foch, Oberlin Noir, Petite Pearl, Solaris, Somerset Seedless, Steuben, Wine King, Worden). On still others they rotted the grapes and/or caused botrytis (Frontenac, Jukka, St Vincent). However, the issue with plastic bags is the SWD, who get inside the plastic bags through the drainage slits on the bottom of the bags.
The vented clamshells protected the grapes on the arbor from raccoons. So far, the raccoons have not figured out how to open these. Wasps, however, enter through the vents, and feast on the grapes. Next, in 2020, I will try clamshells without vents as shown in the photo, but I need to figure out some way to seal them from the SWD.
The fabric bags, Organza bags, and net bags look promising.
The drawstring and flexible fabric, make the organza bags the quickest to tie around the fruit, saving a lot of time. Whether the insects and disease will do damage through the holes in the netting remains to be seen.
The net bags are sturdier and more durable than the Organza bags, but more difficult to get a good seal, due to the stiffness of the fabric. The drawstrings cannot close the top opening completely. This sealing issue may not sufficiently exclude the SWD.
The fabric bags appear to be very good. These are used commercially in Japan. I do not think insects will be able to eat or lay eggs thru this fabric, as they might with the Organza and net bags. Also, they should exclude disease - maybe. The green fabric bags are thicker than the white ones, meaning birds and squirrels will have a tougher time getting to the fruit. Also, the white ones have a thin twist tie vs. a thick sturdy twist tie on the green bags. However, with thinner fabric, when bunched at the top, the white bags yields a better seal, making it less likely the SWD will gain access. On balance, the white bags appear superior. This needs to evaluated by testing in 2020.
Observations in 2020, should tell the tale and reveal which are best suited for the job. My initial guess is the unvented plastic clamshell will work best on the grape arbor against raccoons, if modeling clay can maintain a good seal against the SWD. In the fenced areas, the white fabric bag may work best.
The biggest scourge to overcome is the tiny Asian Fruit Fly (SWD) on grapes and berries.