Q. Several years ago I purchased a Raywood Ash and I have been pruning off infected branches at the beginning of each season. Last week someone had a nursery suggested I apply a systemic containing imidacloprid and clothianidin as active ingredients to try to get some control. Do you know what the problem is? Cicada damage to small limbs on sweet acacia A. The problem you are seeing is most likely cicada damage from egg laying that is now healing. The female cuts a slit parallel along the top of the stem parallel to the branch with her ovipositor (egg laying machinery). The female deposits her flattened oval eggs, about an eighth of an inch long, stacked up against each other along that slit in a nice row. Cicada (probably apache cicada) on the limb of a sweet acacia in late June             If you look at the old twig damage closely, the slit looks like tiny teeth on a saw and that slit is healing nicely. When the eggs hatch a few weeks later, the babies fall to the ground and take into the soil where they feed on tree roots.             The insecticide applied as a soil drench might work because it is systemic. Another option is to apply a soil insecticide drench intended for killing grubs in the soil or eliminating the cicadas on the tree as you see them and before they have a chance to cut a slit and lay their eggs.             Continue to cut off the branches if you want if they are unsightly to you, but the tree will heal fast if it is kept healthy.

Q. For the past three years these little black critters have chewed holes in the leaves of my Mexican Primrose. What are they and how can I get rid of them permanently? Since Mexican Primrose is not a food crop, I sprayed them with Ortho’s Home Defense, but that may not be the best solution. BB sized holes in grape leaves from flea beetle feeding A. Thanks for telling me the insecticide you used but legally you are not supposed to use an insecticide unless the label states it can be used for that purpose. The active ingredient of the insecticide might work on flea beetles but unless there is a given rate of application on the label, then the rate to apply is not known. The rate of application can mean the difference between control or no control. Mexican Primrose and Flea Beetle Damage             Mexican Primrose is notorious for flea beetle damage in the spring and sometimes fall months. Knowing which flea beetle is yours is the first step in getting permanent control. If you elect to go down this path, take five or six flea beetles in a vial of alcohol to the Nevada State Department of Agriculture and ask their entomologist in Reno to identify the type of flea beetle. Once the flea beetle is properly identified, methods of permanent control can be discussed. There is quite a bit of literature on permanent control without chemicals. Flea beetles are quite small             As far as I am concerned, flea beetles are vagabonds and become a problem frequently during the spring, and sometimes fall months. Mark your calendar because they will come near the same date in the spring most years. This date signals you to start looking for them or their damage and apply the proper control measure. Heavy flea beetle damage on grape leaves             Flea beetles last about three weeks and they are gone. They can cause a lot of damage in a noticeably short time. If you see damage during the fall months, mark your calendar. Watch for holes in the leaves that signal their feeding has begun. They hide out on the bottom of leaves so you must spray “up” as well as over the top. Pesticides and Controlling Flea Beetles             Conventional insecticides used for controlling flea beetles include Sevin (active ingredient of carbaryl) or one of the pyrethrins (look for something ending in –thrin in the active ingredients). These must be applied each season you see them. Once damage is done, cut the plant back to get rid of the ugly parts, fertilize, water, and let it regrow.

Farming in the Age of COVID-19 By Renee Pinel Thanks to the COVID-19 pandemic, hand sanitizers and bleach wipes are now a part of our daily lives because everyone understands that we need access to chemicals that  kill the germs and viruses that can kill us. Yet, as things drag on, more and more weary Californians are struggling to stick with shelter-in-place orders. People are venturing out more.  We don’t see as many masks. Businesses are defying state guidelines.  People are starting to let down their guard. This is likely a combination of factors.  One, it is human nature to want to be amongst others.  Two, people are making their own calculations on their risk of exposure, based on individual circumstances.  Three, it is just plain difficult for anyone to sustain intense self-discipline over a long period of time. But we know it is possible to maintain strict standards of safety.  Look at California farmers.  For decades, they have possessed “safety-first” behaviors and practices now deeply ingrained in their DNA.  During the COVID-19 crisis, our farmers have continued to put food on the table and fill food banks while keeping their workers and communities safe.  They have achieved this not by adopting new standards of safety, but by continuing to follow existing requirements for pesticide use and safe food handling. Californians may take this for granted.  But agriculture’s emphasis on safety has been the result of a lot of work, dedication and collaboration between farmers, their communities and government.  Consider: Farmers have been able to continue to produce food because health and safety rules are the norm – not the emergency exception. California farmers have absolutely no interest in short cuts that compromise safety.  They and their families work on the farm. They value their workers. They live in the community.  Our farmers operate under the most restrictive safety standards in the country, if not the world.  Long before COVID-19 became a household word, farmers and farm businesses were investing in the safety of their employees, communities and environment. Scientists with the United State Environmental Protection Agency and California Department of Pesticide Regulation (DPR) conduct the most rigorous pesticide safety testing of anywhere else in the world – more than 300 safety reviews before a product may even be considered for use.  It takes more than seven years to register a pesticide in California. This is the same agency that regulates the sanitizers members of the public are comfortable using at levels that exceed the recommended amounts.  Just as DPR reviews sanitizers designed to kill dangerous germs, they also review products used by farmers to kill dangerous pests. Unlike the sanitizers that the public uses, DPR continues to regulate agricultural products after a purchase is made.  Farmers may only purchase and use an approved pesticide if they receive a “prescription” from state-licensed experts, who dictate terms of every use.  Agriculture follows a complex system of permitting, monitoring, inspections, and reporting to assure that products are only used as labeled. Farms provide personal protective equipment (PPE) and other safety protections to employees. Farmers, farm workers and professional pesticide advisers receive continuous education on the safe use of products. Farmers report all usage, and provide safety buffers around fields and additional precautionary buffers around sensitive sites like schools. To assure all these rules are followed, Agricultural Commissioners and DPR inspectors enforce high standards on farms and other agricultural businesses. These inspections cover the comprehensive array of federal, state, and local worker safety as well as environmental and community human health laws and regulations that cover the agricultural use of pesticide products. During this pandemic, farmers have continued to maintain these high safety standards – even around schools, which are closed.  They have not asked for any current pesticide law or regulation to be suspended or relaxed.  Neither DPR nor the Agricultural Commissioners have suspended or loosened a single regulation during the COVID-19 pandemic. Farmers continue to keep farmers markets, food banks, and grocery produce sections filled with healthy, fresh fruits and vegetables under the same strict standards as they always operate under. While those of us in towns and cities continue to live under special emergency orders that at some point will be relaxed, we can be secure in the knowledge that farmers will continue to protect their employees, communities and the consumers of their produce – long after the Governor lifts his emergency orders. 

Q. I have a well-established, prolific peach tree. About this time every year it loses some of it’s immature fruit and I know that is normal. However, this year it’s losing an abundance of fruit. I’m literally picking up 50-100 peaches a day. I have checked the irrigation and it seem to be fine with drippers at 15 minutes per day, twice a day. A. This will be a challenge. Get ready for an irrigation overhaul! The usual reason for fruit drop is because the fruit was damaged in some way, either from a lack of water to the tree or cold temperatures that hurt the fruit. I don’t think there were cold temperatures this late in the year, so I go back to the water issue. Irrigation Twice a Day I don’t like that you are applying water every day; twice a day in fact! Is there any way that can be changed to less often? That irrigation frequency sounds like watering a lawn or vegetable garden when its really hot and windy out! I don’t know about the amount you are applying, but you are applying water way too often. Peach Tree Irrigation and Woodchips  Fruit trees should have water applied to them twice a week right now and growing in most soils. The applied water should be enough so that the roots of the tree get wet to a depth of about 18 inches. For fruit trees growing in the desert, I like to see a layer of woodchips on the soil surface 3 to 4 inches deep. These woodchips provide a layer that protects the roots from getting too hot, conserves water, prevents most weeds from growing and helps keep the soil dark and rich. This is an irrigation basin around a peach tree filling with water. You are watering so often, unless you have very sandy soil, I imagine the tree roots  are growing about 2 inches deep. They should be growing 18 inches deep. Roots growing shallow like this are cycling back and forth between too dry, too hot or too wet. Roots can’t grow deeper because they are drowning (if you are watering a lot) or getting too hot and dry (if you aren’t watering enough). Thirty minutes of water is meaningless to me. I need to know how many gallons you are applying and where it’s being applied. What to do?  This is tricky because the tree roots need encouragement to grow deeper and hot weather is already here. Root growth would be better starting in October when temperatures are cooler. Do not apply any more water using the current irrigation schedule of twice a day. Free woodchips from local arborists who wanted a place to dump clean mulch. Cover all the soil under the tree’s canopy with 3 to 4 inches of woodchips. Apply water to the soil 12 inches from the tree trunk all the way to the edge of the canopy. This can be done by constructing a donut around the tree trunk 6 to 8 feet in diameter. Basin beneath grapes that didn’t hold the water. It was repaired but easy to see! The inside of this donut must be flat with a circular wall that is 3 to 4 inches tall. Fill the inside of this donut with a 1-inch layer of compost with woodchips on top. Fill the inside of this donut with water once a day. At the end of August, begin watering every other day. At the end of September water every third day. By December you should be watering once a week. Rectangular basins with flat insides to hold water but let people and equipment through. I generally figure that most peach trees that produce an abundance of fruit should only be allowed to keep about 1% or less of all the fruit produced by a tree. I’m assuming you are removing fruit that are closer than three or 4 inches apart all through the tree. When peaches are pruned in the wintertime about half of all their branches are removed from the limbs. The removal of these branches are so that the remaining branches produces fewer fruit and there is less thinning to do. Otherwise there’s a lot of limb breakage because of the weight of the peach fruit.

Q. I found your blog and am hoping you can tell me if this tree in the picture is a Bay Laurel. I have looked at pictures of Carolina Cherry trees that also look similar. This tree has supports which I know need to be removed at some point. The tree was planted by my builder in February of last year. A. Looks like Bay Laurel to me. Bay Laurel is a Mediterranean tree and more tolerant of our desert climate than Carolina Cherry Laurel. Carolina Cherry Laurel is native to the southeastern US and not tolerant of desert conditions without proper site selection, soil preparation and watering.             One easy way to tell the difference is to crush the leaves and smell the herbal (Bay) aroma of Bay Laurel. Bay Laurel leaves are pungent in their aroma. When you crush the leaves of Carolina Cherry Laurel they have an aroma of cherry rather than herbal.              The second way is to look for round “glands” at the base of the Carolina Cherry Laurel leaf where the leaf is attached to the petiole (leaf stem). These “glands” are characteristic of many plants in this genus (Prunus). Click here to see the glands on P. serrulata

Q. We have three Japanese Blueberry in our yard; two in the backyard and one in the front. All three have dead branches yet there are scattered green leaves above them. There are far more green leaves at the bottom of the three plants. Is it possible this is due to a lack of water? A. Japanese blueberry is not a good choice for a desert climate and soils but will handle it if planted in the right location, good soil prep and regular watering. If planted in a hot microclimate with alot of reflected heat and light it gets sunburn easily and dieback. https://xtremehorticulture.blogspot.com/2015/07/more-problems-growing-japanese.html Japanese blueberry is from Far Asia and not many deserts there so it is not really a desert plant.It grows better in a Mediterranean climate like you find in coastal CA. It grows better in a Mediterranean climate like you find in coastal CA. When grown there it is much easier to manage. What To Do So if the soil is covered in rock, if the water amount is not increased as the plant gets bigger then chances are good there will be problems.  Not sure what the reason is for dead branches but most likely related to soil management (not covering the soil in woodchips and not amending the soil so its more like soils in the Far East) or water or both. Borers It is possible to be a borer problem but I would need more information. Remove dead branches. Improve the soil and apply water to a larger area under the plant.

Q. The bottom layer of palm fronds turned an orange – yellow color almost overnight. Is this from too much water or not enough water? Color change if the fronds of this Canary Island palm signals the owner to remove them. A. Neither, the cause of it turning orange or yellow is natural. These orange and yellow colors are natural, masked by the strong green color that the chlorophyll provides. We see the same color changes in leaves in the fall color of trees.             The bottom layer of fronds die a natural death. As these lower fronds approach death due to old age and shade, some of the minerals in the leaves are absorbed back into the palm, first turning the lower fronds orange or yellow and eventually brown. Sometimes these color changes occur quickly and other times more slowly.             The nitrogen, phosphorus and potassium move out of the frond first followed by magnesium, chlorine, zinc and molybdenum. Lesser mobile nutrients are left behind which include sulfur, iron, boron, and copper. These would be the dominant minerals remaining if these palm fronds were used to make compost. This color change is your signal to cut and remove palm fronds.

Q. I watched your pruning videos on YouTube and learned a lot! Is it possible to reduce the size of a standard sized apple tree to a dwarf size this way? A. Probably not. Standard sized apple trees may grow to 35 or 40 feet in height. You might be able to keep a standard sized tree under 20 feet tall (maybe 15 feet if you’re really aggressive) through pruning but I don’t think you will get it to eight feet tall which is what I aim for in pruning semi dwarf trees for backyards. I call the size of these fruit trees “ladder less”. The standard sized apple tree is just too vigorous for pruning to short heights. Standard Sized Apple Tree Is Big             Standard sized apple trees normally grow 30 to 40 feet tall. Buying these trees on semi dwarfing rootstocks will keep them smaller than this but it depends on which semi dwarfing rootstock the tree has been grafted onto. I have found that the M111 semi-dwarfing apple rootstock is probably the best semi-dwarfing apple rootstock for backyards in our climate.             Using this semi-dwarfing rootstock, I have been able to keep Pink Lady and Mutsu apples, for instance, pruned at eight feet through appropriate pruning methods. Apple trees grafted onto M111 rootstock will normally get to 80% of its mature height if left unpruned.             Nurseries sell fruit trees with a tag that calls the tree a “semi dwarf” because most people don’t know the different kinds of semi dwarfing rootstocks. In our area an apple that is labeled as semi dwarf is most likely grafted on to M111 rootstock.  There are online stores for fruit trees, such as Grow Organic and Bay Laurel, that specify the rootstock used and the most common semi-dwarfing rootstock available on apples for backyards in the Western US is M111.

Q.. I am writing you to find out how often should I be watering my trees and shrubs. The weather got hot so quickly that I’m really not sure when to water. I have a California Pepper Tree, 2 palm trees (a canary date and a Mediterranean fan ) and 5 Japanese boxwood shrubs.  Any help you can give me is appreciated . A. There are two questions that need answering: how many minutes to water each time and secondly how often. https://wateruseitwisely.com/100-ways-to-conserve/landscape-watering-guide/plant/ The number of gallons of water given to a plant depends on its size; small trees are watered 18 inches deep, medium-size trees 24 inches deep and large trees 36 inches deep. Establishing the Number of Minutes The number of minutes depends on the soil you have and how big the tree is. Small trees are watered 18 inches deep. Medium-size trees are watered 24 inches deep. Large trees are watered 36 inches deep. Always apply the water to wet the soil at least half of the area under the tree’s canopy. Small trees are less than 20 feet tall. Medium-size trees are 20 to 35 feet tall. Large trees are above 35 feet tall. Your soil and how big the tree is so I can tell you the number of minutes. You have to figure that out for yourself. To do that I use a 3/8 inch diameter rebar 4 feet long. If the water didn’t go deep enough, water more minutes until you get there. A 4 foot length of three-eighths inch rebar I use for measuring how deep water penetrates in the soil after an irrigation. Right after I irrigate I push this rebar into the soil in three locations, where the soil is wet, as deep as I can. The rebar pushes in easily if the soil is wet. When the water doesn’t go any deeper and the soil isn’t wet anymore it’s hard to push. Watering How Many Times A Week Each time I water I use the number of minutes it takes to get the water to that depth. That doesn’t change. What changes is how many times I water each week. This is for non-desert plants.For desert plants water less often but give them the same amount of water as I mentioned above. Winter months every 10 days or more Starting February 1 every seven days About mid April twice a week About June 1 three times a week In the wintertime I water to that depth about every 10 days or longer. About February 1 I start watering once a week. Around the middle of April I water twice a week. Around 1 June I start watering three times a week. If it gets really hot I might water four times a week. A 3 to 4 inch layer of woodchips or rock helps keep the soil wet. I only use rock with trees that come from the Southwest deserts. All the rest of the trees I use woodchips. By the way, none of the plants you mentioned in your question are desert plants.

Summer watering restrictions begin May 1   Summer is almost here and it’s time to turn up the heat on saving water! Beginning May 1, seasonal watering restrictions allow watering up to six days a week and prohibit landscape irrigation on Sundays, as well as between the hours of 11 a.m. and 7 p.m., when water can be lost to intense heat and high winds. Water your landscape in the early morning hours before sunrise to reduce evaporation. While watering is permitted up to six days a week through Aug. 31, just because you CAN doesn’t mean you need to. Adjust watering gradually as temperatures increase; plants on drip need water less often than sprinklers on grass. Find more watering tips.