Posts Tagged: pluot
Got a Plum Gall on your Fruit Tree?
Client's Request: I'm a trapper in the Ag Department. We have been looking for plum bud gall mites in the county. I recently came across this plum tree with a huge growth or gall, it's 8" long and 7" wide on the underside of a branch, the tree is around 15 years old. Homeowner wants to know what it is and what should be done about it. The tree is in Pittsburg. Any ideas?
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about a very large gall on this 15 year old plum tree in Pittsburg.
I believe this is a gall caused by the bacterium Agrobacterium tumefaciens commonly referred to as crown gall mite or possibly Plum Bud Gall Mite (Acalitus phloeocoptes (Nalepa)). Crown gall, as its name implies, typically appears at the crown of a plant, where the trunk enters the soil but it also can infect the main trunk and side branches. Plum trees are among a long list of plants commonly infected by crown gall including many popular home garden fruit trees (pluots, etc.).
The surface of crown galls and wood underneath is the same color as healthy bark and wood. However, when cut with a knife, crown galls are softer than normal wood and lack the typical pattern of annual growth rings. Galls can be tiny and smooth on young plants but usually are rough and sometimes massive on older trees.
Crown gall appears to have a relatively minor effect on most older plants which is the situation you found. Since this tree is 15 years old and the gall appears to encompass a major part of the main branch I would suggest leaving it be. If the distal portion of the branch starts to decline then the branch can be removed back towards the trunk thereby removing the gall.
Without further inspection of the gall here in our office, another possibility is the Plum Bud Gall Mite (Acalitus phloeocoptes (Nalepa)) which are well described in the Santa Clara County UCCE link below.
Following is a link to a UC Integrated Pest Management website that explains crown gall http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/crowngall.html
and here is a Santa Clara County UCCE link to Plum Bud Gall Mite:
http://mgsantaclara.ucanr.edu/files/300211.pdf
We could give a more conclusive response if you would bring a sample to our offices during our office hours described at the bottom of this response.
I hope your homeowner will be relieved. Good luck.
Help Desk of the UC Master Gardener Program of Contra Costa County (EDC)
Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone: (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Biog.
In the backyard orchard, pluot reigns supreme
When it comes to planting stone fruit at home, pluots are the way to go, says Chuck Ingels, UC Cooperative Extension advisor in Sacramento County. Cherries are delicious, but with a new maggot pest, are hard to grow. Peaches and nectarines are susceptible to leaf curl disease, which is challenging to manage because the most effective products have been removed from store shelves. Apples and pears can suffer from fire blight and coddling moths worms.
“Pluot” is a trade name for varieties of interspecific plum-apricot bred by private Modesto breeder Floyd Zaiger. Pluots’ skin is typically dappled but smooth and without the bitterness in the skin of plums. The flesh is unusually sweet and juicy with complex plum-apricot flavors.
“I really like Flavor Grenade,” Ingels said. “The taste just explodes in your mouth. Another good one is Dapple Dandy, which is a little later.”
Flavor Grenade is a large fruit with oblong shape. The skin has a red blush on green background, and the flesh is a juicy yellow. Dapple Dandy has mottled pale green to yellow, red-spotted skin and red or pink juicy firm flesh.
At the UC Cooperative Extension Fair Oaks Horticulture Center in Sacramento, Master Gardeners are creatively planting and pruning pluots and other fruit trees to make them easier to harvest and take less space. The best time to plant is early- to mid-winter.
“We have fruit bushes at the horticulture center,” Ingels said. “It works out really well.”
Fruit bushes are standard or semi-dwarf trees kept small by periodic summer pruning. Fruit bushes can be managed without a ladder and multiple species and varieties can be grown in relatively small areas. When bare-root planted in the winter, the trees are headed to knee height. In late spring and again in the summer, new growth is cut in half. This pruning regimen continues until trees reach the desired height - usually two years. For the life of the tree, it is pruned to a size manageable from the ground.
“The main concern is keeping them tame,” Ingels said. “For pluots, there is just one dwarfing rootstock – Citation.”
Pluots, like plums, will also need a pollinizer of a different variety to ensure good fruit set. Most pluot varieties will pollinize another pluot variety. Another option is planting certain varieties of plum to pollinize the pluot.
At the Fair Oaks Horticulture Center, Master Gardeners are experimenting with a number of planting arrangements, such as planting two to four different trees in one hole. Trees grown in this close proximity combine to form a bush the approximate size of one tree grown alone. For more ambitious gardeners, fruit trees can also be carefully trained into an espalier or other design. For examples, see the Fair Oaks Horticulture Center website.