Posts Tagged: rind
Satsumas and Navels - Too Late?
There have been some complaints about satsuma mandarin fruit having problems. These are prone to a rind/skin/peel breakdown when the fruit is not picked promptly. It's not clear what the cause is - wet winter, warm winter - but it is less of a problem if the fruit is picked when it is mature. A lot of the time in southern California, satsumas will develop good flavor and sweetness, but for lack of cool weather, they don't turn bright orange, a hallmark of the fruit. So growers will leave the fruit on longer, hoping for color, but the fruit becomes over mature, and more susceptible to breakdown. This weakening of the peel then opens it up to infection by fungi, such as Alternaria. In warm winters, the peel matures more rapidly and is more susceptible. Early maturing varieties like ‘Okitsuwase' are especially prone to breakdown later in the season, since their rind matures earlier. They end up being a mess, as can be seen in the photo below.
Navels can have a similar problem in these winters with erratic rainfall. Common wisdom is you don't irrigate in the winter, right? Wrong. With no, low and widely spaced rain events, the tree roots dry out, and rewet with rain. Navels are building their sugar in the winter and they become suction balls for water as the sugar increases. The fruit will continue to grow as the tree takes up water. When the roots run out of water, and then are suddenly rewetted during this period, the fruit can suck up water so rapidly that the skin cant expand fast enough and will split. So this is what happens with uneven irrigation or rainfall this time of year. One of those abiotic problems in citrus.
satsuma rind breakdown
split navels
Meyer Lemons Too Big?
Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: What do you think caused my lemons to be too big (Picture 1). The second picture has a normal size Meyer lemon next to my too big Meyer lemon. All the lemons on the tree this year were like this. Last year most of the lemons were normal size except for three. The tree is about 8 to 10 years old. It's always been in the same pot on my deck. I fertilize it about three times a year. I appreciate any advice you can give me.
Response from the MGCC's Help Desk: Thank you for contacting the UC Master Gardener Program Help Desk with your question about your Meyer's lemon. It was a pleasure to talk to you in order to find out a bit more about your dwarf Meyer Lemon that has over-sized lemons with thick rinds and little juice.
After completing some research, reviewing the photograph of your 10 year old potted plant, and learning more about your fertilizing and irrigation routines, we have some information and suggestions to share with you that we hope you will find helpful.
Fruit Left on the Tree Too Long
Lemons may develop thick, puffy skin when left on the tree for too long after they ripen. You can wait to pick until the lemons have turned fully yellow, but to ensure juiciness and thinner skins, pick them while there is a little green still on the fruit.
Environmental Moisture and Watering
Dry weather or infrequent watering may cause your lemons to have a dry pulp. Water stress may prompt the tree to absorb moisture from the fruit's pulp, resulting in lemons with little juice. This reabsorption may also occur if you leave the lemons on the tree too long after they ripen. To prevent water stress, keep the top 5 to 6 inches of the soil moist; for dwarf lemons grown in a container, keep the top 1 to 2 inches of soil moist. Alternatively, excessive moisture in the air from high humidity levels may cause puffy rinds with a coarser texture and duller color, though the amount of juice may not be affected.
It's Time to Repot your Meyer Lemon
It is probably time to repot your Meyer Lemon. Potted lemon trees require repotting every two to three years, or when the roots begin growing out the drainage holes. The best time to repot your tree is in spring during heavy growth so it has time to establish in the new container.
Select a container one size larger than the current container. For example, upgrade from a 5 gallon to a 7-gallon pot or a 7-gallon to a 15-gallon pot.
Fill the new pot one-fourth full with a potting soil similar to the type used in the old container. Water the soil until it's evenly moist and the excess just begins to drain from the bottom.
Insert a trowel or knife between the soil and pot sides to loosen the root ball from the container. Grasp the tree near its base and lift it up while a second person pulls the pot downward.
Thoroughly examine the roots and locate any roots that are completely encircling the root ball. Slice through these roots with a clean knife; otherwise, they may constrict the root ball as they grow and cause the tree to die. Remove any dead root material.
Set the tree in the new pot. Adjust the depth of the soil beneath the root ball so the top of the root system sits 2 inches beneath the pot rim. The top of the roots should be just beneath the soil surface, and crown roots (root collar area) should show above the soil line.
Fill in around the roots with additional soil until the lemon tree is potted at the same depth it was at previously. Water thoroughly so the soil settles around the roots and add more soil, if necessary.
Possibly Over Fertilizing Your Tree
Most mature citrus require regular fertilization with nitrogen. Your fertilizer should have more nitrogen (N) than phosphorous (P) or potassium (K). Use at least a 2-1-1 ratio. Typically, most other nutrients are available in sufficient amounts in the soil. Nitrogen should be applied in January or February just prior to bloom. The second application then can be applied in May and perhaps a third in June. Avoid late-season fertilization as it may affect fruit quality, delay fruit coloring, and make the rind tough. Dwarf plants or trees in containers with restricted root space may require less fertilizer. Be careful not to over-fertilize as this could cause excessive new growth, which makes trees susceptible to other disorders.
Here is a list of citrus care articles that you may find helpful for the continuing health of your tree:
http://homeorchard.ucanr.edu/Fruits_&_Nuts/Citrus/
http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/citrus.html
//ucanr.edu/blogs/slomggarden/blogfiles/4260.pdf
We certainly hope this information is helpful to you. Please do not hesitate to contact us again should you have any other questions about your lemon tree or other horticultural needs.
Help Desk of the Master Gardener Program of Contra Costa County (WHM /SLH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/).
Drought Induced Problems in Our Orchards
Drought Induced Problems in Our Orchards
Abiotic disorders are plant problems that are non-infective. They are not caused by an organism, but through their damage, they may bring on damage caused by organisms. Think of a tree hit by lightning or a tractor. The damage breaches the protective bark which allows fungi to start working on the damaged area, eventually leading to a decayed trunk. It was the mechanical damage, though that set the process in motion.
Too much or too little water can also predispose a plant to disease. Think of Phytophthora root rot or even asphyxiation that can come from waterlogging or too frequent irrigations.
Salinity Effects from Lack of Water
Lack of water and especially sufficient rainfall can lead to salinity and specific salts like boron, sodium and chloride accumulating in the root zone. This happens from a lack of leaching that removes native soil salts from the root zone or the salts from the previous salt-laden irrigation from the root zone. These salts cause their own kind of damage, but they can also predispose a tree to disorders, disease and invertebrate (insect and mite) damage.
Lack of water and salt accumulation act in a similar fashion. Soil salt acts in competition with roots for water. The more soil salt, the harder a tree needs to pull on water to get what it needs. The first symptom of lack of water or salt accumulation may be an initial dropping of the leaves. If this condition is more persistent, though we start to see what is called “tip burn” or “salt damage”. Southern California is tremendously dependent on rainfall to clean up irrigation salts, and when rain is lacking, irrigation must be relied on to do the leaching
As the lack of leaching advances (lack of rainfall and sufficient irrigation leaching) the canopy thins from leaf drop, exposing fruit to sunburn and fruit shriveling.
Leaf drop and fruit shriveling in avocado.
In the case of sensitive citrus varieties like mandarins, water stress can lead to a pithy core with darker colored seeds, almost as if the fruit had matured too long on the tree.
Total salinity plays an important factor in plant disorder, but also the specific salts. These salts accumulate in the older leaves, and cause characteristic symptoms that are characteristic in most trees. Boron will appear on older leaves, causing an initial terminal yellowing in the leaf that gradually turns to a tip burn.
Often times it is hard to distinguish between chloride, sodium and total salinity damage. It is somewhat a moot point, since the method to control all of them is the same – increased leaching. There is no amendment or fertilizer that can be applied that will correct this problem. The damage symptoms do not go away until the leaf drops and a new one replaces it. By that time hopefully rain and/or a more efficient irrigation program has been put in place.
The Impact of Drought on Nutrient Deficiencies
Salinity and drought stress can also lead to mineral deficiencies. This is either due to the lack of water movement carrying nutrients or to direct completion for nutrients. A common deficiency for drought stressed plants is nitrogen deficiency from lack of water entraining that nutrient into the plant.
This usually starts out in the older tissue and gradually spreads to the younger tissue in more advanced cases.
The salts in the root zone can also lead to competition for uptake of other nutrients like calcium and potassium. Apples and tomatoes are famous for blossom end rot when calcium uptake is low, but we have also seen it in citrus. Low calcium in avocado, and many other fruits, leads to lower shelf life. Sodium and boron accumulation in the root zone can lead to induced calcium deficiencies and increased sodium can also further lead to potassium deficiencies. Leaching can help remove these competitive elements.
Drought Effect on Tree Disease
Drought and salt stress can also lead to disease, but in many cases once the problem has been dealt with the disease symptoms slowly disappear. They are secondary pathogens and unless it is a young tree (under three years of age) or one blighted with a more aggressive disease, the disease condition is not fatal. Often times, in the best of years, on hilly ground these diseases might be seen where water pressure is lowest or there are broken or clogged emitters. The symptoms are many – leaf blights, cankers, dieback, gummosis – but they are all caused by decomposing fungi that are found in the decaying material found in orchards, especially in the naturally occurring avocado mulch or artificially mulched orchards. Many of these fungi are related Botryosphaerias, but we once lumped then all under the fungus Dothiorella. These decay fungi will go to all manner of plant species, from citrus to roses to Brazilian pepper.
Another secondary pathogen that clears up as soon as the stress is relieved is bacterial canker in avocado. These ugly cankers form white crusted circles that ooze sap, but when the tree is healthy again, the cankers dry up with a little bark flap where the canker had been.
Drought Effect on Pests
Water/salt stress also makes trees more susceptible to insect and mite attack. Mites are often predated by predacious mites, and when there are dusty situations, they can't do their jobs efficiently and mites can get out of hand. Mite damage on leaves is often noted in well irrigated orchards along dusty picking rows
Many borers are attracted to water stressed trees and it is possible that the Polyphagous and Kuroshio Shot Hole Borers are more attracted to those trees.
And then we have conditions like Valencia rind stain that also appears in other citrus varieties. We know it will show up in water stressed trees, but we aren't sure what the mechanism that causes this rind breakdown just at color break. Could it be from thrips attracted to the stressed tree or a nutrient imbalance, it's not clear?
Water and salt stress can have all manner of effects on tree growth. It should lead to smaller trees, smaller crops and smaller fruit. The only way to manage this condition is through irrigation management. Using all the tools available, such as CIMIS, soil probes, soil sensors, your eyes, etc. and good quality available water are the way to improve management of the orchard to avoid these problems.
Scroll down for Images
Tip Burn, notice sun burn bottom right hand fruit
Endoxerosis with dried out core
Boron toxicity
Nitrogen deficiency
Blossom end rot
Potassium deficiency
Bot gumming in lemon
Black Streak in Avocado
Bacterial Canker
Citrus red mite
Polyphagous Shot Hole Borer damage on avocado
Valencia Rind Stain
avocado drought canopy
nitrogen deficiency
endoxerosis 4
boron toxicity citrus 1
blossom end rot lemon
potassium deficiency avocado
gumming dothiorella
avocado black streak 1
bacterial canker avocado
citrus red mite
PSHB damage
Satsuma Rind Disorder
There was a lot of odd looking, water-soaked Satsuma fruit showing up this year along the coast. It was showing up as late as March since fruit can hang so much longer along the coast than the Central Valley and hotter areas. It turns out its an abiotic issue and is more associated with the cooler, coastal environment. Recently a "Gold Nugget" mandarin came in that had a very similar look to the rind. This variety doesn't have immediate satsuma parentage, but who knows what is in its past. The disorder is most commonly associated with cool, foggy or rainy conditions. In the fall we had those conditions and maybe that's what set it off. Later, secondary fungi move in to colonize, the depressions that first occur.
mandarin rind disorder