What causes Sudden Oak Death in trees and plant life? Sudden Oak Death, or SOD, is caused by the pathogenic fungus Phytophthora ramorum. This waterborne mold pathogen infiltrates plants and trees through contaminated irrigation water, wind-blown rain, infected plants, and contaminated pots and soil mixes. This fungus is also associated with other tree wellness issues like Ramorum leaf blight, Ramorum dieback, and Phytophthora canker.
Are your palm trees safe from invasive Bay Area pests? The palm weevil, which crossed the US-Mexico border several years ago, is continuing to spread north. A study by the University of California recently uncovered that the palm weevil flies much faster and spreads more rapidly than previously anticipated, and how easily area trees could fall prey to this palm tree pest.
Palm weevils attack many palm species throughout the region, including fruit-bearing date palms, coconut palms, sago palms, African oil palms, and Washingtonia fan palms. If the palm weevil impacts date palms in Imperial and Coachella, their damage could cost millions. If you fear a palm weevil infestation, contact an Arborwell tree wellness expert immediately. Palm weevils can kill a Canary Island palm tree in just 49 days. Hundreds of palms in Tijuana and San Diego have already succumbed to the pest. Worsening matters, the palm weevil also carries a roundworm on its body that is a known vector for red ring disease, which is lethal to date palms.
Unlike their relative, the red palm weevil, brought to the US from Southeast Asia for food, the jet-black South American palm weevil may prove harder to eradicate. The pest is spreading naturally from neighboring Mexico, stretching its wings as far east as Texas and as far north as Bonita, CA. Once infested, a single palm tree could host up to 1,000 weevils. Females of the species are remarkable flyers, capable of covering 61-87 miles in a single day, increasing the likelihood of infestation and widespread destruction.
With their prolific procreation and capacity for flight, it is essential that we all work together to prevent and control the spread of the palm weevil. Early identification of infested trees is crucial. If you see signs of crown damage or drooping/dead fronds, we recommend scheduling a complimentary assessment from an Arborwell certified arborist right away. We recommend removing infected trees from your Bay Area apartment community, HOA, commercial office, retail space, industrial park, or government facility immediately. This will not only stop the spread of the pests but prevent collapsing trees from injuring bystanders.
Identify and eliminate palm weevils fast with help from Arborwell Professional Tree Management. Contact us to schedule a complimentary tree assessment from a certified arborist for your San Jose, San Francisco, Walnut Creek, Seattle, Palo Alto, Menlo Park, Hayward, or Oakland commercial property today.
Do your usual tree management tactics seem to be falling short? The California climate, temperature extremes, and pollution can certainly do a number on landscaping, impacting tree health. However, the Arborwell team knows that disease may also be to blame. How can you distinguish environmental stress from illness? Check the trees on your California property regularly, watching for signs of these common tree diseases.
Anthracnose is a fungus that affects a variety of plants and trees. It thrives in warm, moist conditions and multiplies very quickly during rainy spells, spreading through infected plant debris. Our plant health care experts identify it by the dark, sunken lesions it produces on affected flowers, fruits, leaves, and stems, which begin as small, irregular yellow-brown spots that darken and spread. Fortunately, with proper tree care from our knowledgeable arborists, anthracnose is not lethal.
The Arborwell team frequently encounters this bacterial disease in the early spring. Though it doesn’t affect a wide variety of tree types, it is incredibly contagious and can cause significant damage very quickly. Fire blight attacks all parts of the tree, including blossoms, leaves, and branches, giving them a dark brown or black scorched appearance. It spreads through many vectors, including wind, rain, insects, and birds, and is frequently seen on California’s apple and pear trees. Left unchecked, it can kill a tree, necessitating removal and replacement.
Fusarium wilt is another widespread fungus we frequently see throughout the state. It is known for attacking food crops such as tomatoes and bananas and is one of many diseases affecting California palm trees. Fusarium oxysporum can live indefinitely in the soil without access to a living host and spreads easily, making it difficult to eradicate. The infection begins in the roots, interfering with water transport, causing lower (older) leaves to wilt and yellow. The disease then progresses to new growth until the plant eventually dies.
Experienced arborists know that weak and diseased plants are naturally more susceptible to pests. Infestations can quickly go from being an unsightly nuisance to a major problem, claiming the life of the trees on your commercial property. Watch out for these common offenders on sick or diseased trees:
Identify and manage common tree diseases in California cities with the help of Arborwell Professional Tree Management. Fill out our online form to schedule an arborist assessment for your ailing trees, or contact us at today.
Anthracnose, Fire Blight, fusarium wilt, tree health, tree management
There is no shortage of palm trees in San Diego. Sadly, there’s also no shortage of palm tree pests. In recent years, invasive, non-native insects have taken on a toll on these icons of the West Coast, making it challenging to keep your palm trees looking their best. Which types of palm tree pests do our San Diego arborists find causing the most damage to area landscapes?
The Arborwell team frequently encounters red palm weevils when compiling arborist reports. One of the biggest threats to area palms, these giant 1.5-inch red-brown insects feed on over 40 different palm species. They have caused millions in economic losses globally.
A delicacy elsewhere in the world, these pests are believed to have been introduced when they were brought into the U.S. for food. However, red palm weevils can fly about a half a mile per day, and they quickly spread through the region by flight and through palm tree sales. Difficult to detect, no one identified the escapees until landscapers noticed area palms slowly dying, the trees looking brown and droopy.
Red palm weevils are tunneling insects with a long, slender snout, which the female uses to penetrate the bark of palms to deposit her eggs. Once hatched, the larvae burrow deep into the tree, consuming it from the inside out, and leaving behind a foul-smelling mush-like substance. Because damage begins high in the tree, where new frond growth emerges, the sound of the gnawing insects often goes unnoticed until tree wellness suffers.
Our arborists are familiar with the signs of red palm weevil infestation, which we often encounter during routine trimming. Our trained professionals know to watch for signs of red palm weevils, including larval tunnels and feces within leaf bases in the tree canopy. We can help you quickly quarantine and rid your grounds of these invasive pests using traps and trunk injection treatments.
Unlike the massive red palm weevil, polyphagous shot hole borers are small; only the size of a sesame seed! Though tiny, these beetles have decimated hundreds of thousands of trees in Southern California, including healthy palm trees. Polyphagous beetles were discovered in the late winter of 2012, infecting several backyard avocado trees in Los Angeles, and have since spread to surrounding areas.
The pests were possibly introduced via shipments from Southeast Asia, though their specific origin remains unknown. The pest cannot fly but can hitchhikes in landscaping equipment, tree waste, and firewood. Another outbreak occurred a year later, found to be a second species of polyphagous beetle, the result of a second introduction rather than a spread of the L.A. infestation.
Polyphagous shot hole borers attack dozens of landscape tree species, tunneling within. They carry Fusarium, a fungus causing fusarium dieback, which affects hundreds of species. Unlike red palm weevils, these wood-boring beetles do not eat tree bark. They lay eggs in certain species that serve as reproductive hosts, such as California, Fountain, Jelly, and King palms, among many others. Like tiny farmers, they also use the tunnels they excavate to grow Fusarium, their primary food source, cultivating it within infested trees.
Our arborists can quickly recognize the signs of polyphagous beetle infestation and Fusarium dieback, dubbed the shot hole borer-fusarium dieback (SHB-FD) complex. Property owners typically notice limb dieback from the fungus, which blocks the transport of water and nutrients to leaves. When we see tiny little pinholes in tree bark, with sawdust-like powder around the holes, we scrape back bark to look for the tiny beetle in its circular galleries. As ongoing trials using natural predators progress, we use tree injection treatments to exterminate the polyphagous shot hole borer, devising a customized tree care plan to protect your landscape.
Are pests taking a bite out of your landscape? Arborwell Professional Tree Management can help you control many types of palm tree pests in San Diego. Contact us at to speak to one of our ISA certified arborists, or to schedule an examination of potentially infested trees today.
palm tree pests, palm trees, palm weevil, tree health, weevil
We are seeing more trees this summer that look green and healthy one week and within a few weeks entire branches turn brown and leaves dry up, the most common cause of this problem is verticillium wilt. Verticillium is a soil borne root disease that usually infects through the root as they contact verticillium spores in the soil.
Many trees are susceptible to verticillium including, arborvitae, birch, crabapple, ginkgo, maple, oak, pine, spruce and tulip trees. What makes this disease so difficult is that by the time we typically see damage, the disease has spread too far and tree removal is usually the only option. Once a soil is infected it is very difficult to kill the spores, so it usually remains in the soil indefinitely. However, there are some ways to protect your trees and reduce the chance of infection.
My tree was looked good last week and now this week it has several branches with dead leaves, what’s wrong?
This is most likely verticillium wilt, which is caused by a soil fungus that can lie dormant in the soil for many years. When the roots of susceptible plants grow close to the spores, the fungus germinates and infects the roots of the plants through wounds or natural openings. The fungus spreads into the branches through the plant’s vascular system and at the same time, causes the plant cells to “plug” themselves. Once this happens, water can no longer reach the leaves and they wilt and die, often all along one or branches at a time. It often happens quite suddenly, although in some plants the leaves turn yellow or brown first.
Why is this so prevalent now?
That is a hard question to answer but yes, we are seeing more of this disease this summer and fall. Essentially, our trees are still recovering from the drought of several years back. Their root systems were compromised. The moisture this spring really encouraged new rooting and also encouraged more root diseases overall.
How can I be sure my tree has this disease?
On certain trees – maples and tulip trees in particular, elongated dead areas of bark, called cankers, may appear on diseased branches or trunks. On most trees with the disease, the sapwood of smaller branches is streaked brown or black, occasionally in other colors too. However, since not every tree exhibits this discoloration, testing tissue in a lab may be recommended to confirm the diagnosis.
Will my tree survive?
Unfortunately, usually not. There seem to be two forms of the disease, one in which plants die slowly over several years and another where they die rapidly within a few weeks. Trees that show minor branch wilt one year may show more the next year or may not show symptoms again for several years.
Is there anything I can do for the other trees on my property?
There are ways to help protect your trees, particularly if they don’t show signs of the disease. First make sure the tree is not stressed – proper water and proper feeding are important here. Secondly, there are some good guy fungal species that do battle against this root disease and several others, too. The good guys inoculate onto the roots of a tree and fight and kill these fungal pathogens. (I like to use the analogy of probiotics that help our digestive system stay healthy.) But this process should start before verticillium wilt becomes established in the tree.
Our arborists at Arborwell can recommend a protective program for the trees that are susceptible on your site. Fill out the form below to get in contact with an arborist today!
preventative tree care, Prevention, root disease, tree care, verticillium wilt
When large trees lose their leaves in mid-summer, we tend to panic, and often for good reason. We tend to think of water problems or diseases as the main cause, but sometimes it may be a small insect that is hard to spot. Psyllids are small insects that suck plant juices and excrete sticky honeydew on which blackish sooty mold grows. Some species secrete pale or white wax masses, pellets, strands, or coverings called lerps. They affect many species of trees in our region, but the most common are Eucalyptus, peppertree, citrus, acacia, laurel and tipu or rosewood.
My eucalyptus trees are losing lots of leaves, what could be wrong?
There are several reasons why eucalyptus leaves drop their leaves in large amounts. If you see small, whitish “caps” on the leaves, this is a type of “psyllid” called “redgum lerp psyllid”. This is one many psyllid types that are common in our region.
What other damage can psyllids cause?
High psyllid populations reduce plant growth and cause tip damage, discoloration or dieback. Certain species can cause premature leaf drop. Excessive honeydew creates a sticky mess on cars and surfaces below trees.
Do psyllids damage other trees in my landscape?
There are over 160 psyllid species that occurs on landscape plants in California. Each kind of psyllid feeds only on one plant species or one closely related group of plants. Most psyllids native to California are relatively uncommon and rarely become pests. But some can cause extensive damage. These are generally psyllids that have become pests on trees that are originally from other countries. The most important tree damaging psyllids occur on acacia, eucalyptus, olive, peppertree, laurel and citrus.
I’ve heard about citrus trees dying or being taken out, is this the problem with them?
Well, sort of. A relatively new psyllid pest (Asian citrus psyllid) has been introduced into parts of California. The insect itself doesn’t kill citrus trees, but it can introduce a disease called “Citrus Greening” that is essentially fatal to them. If allowed to become widespread, it is feared the California citrus industry will be wiped out. Currently, the agencies involved are heavily involved in scouting, insect control and plant removal efforts in regions that are most affected. Being vigilant about scouting and controlling this pest when found is very critical.
What can I do?
Your Arborwell arborist can identify locations where Asian citrus psyllid, Redgum lerp psyllid (or other types) are doing the most damage and recommend a treatment program to recover your trees and to keep them healthy. They can also recommend a proper plan for citrus trees on your property if you are close to an area affected by Asian citrus psyllid.
Fill out the form below to contact an Arborwell arborist and find out more about Psyllids and what we recommend for preventing damage and for helping trees recover if they have been attacked by high populations of Psyllids.
arborist, eucalyptus, insect, preventative tree care, psyllids, tree care
