Prevention

palm tree maintenance

Bay Area Pests: The Palm Weevil

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 Pose a Substantial Threat to Trees in the Bay Area

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.

Black Palm Weevils May Be Harder to Eliminate Than Red Palm Weevils

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.

Timely Pest Control is Crucial to Managing Palm Weevil Infestation

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.

palm weevil, pest conrol, pests, Prevention

leaves browning due to vert wilt

Arbor-wellness: Verticillium Wilt

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

Drought Tolerant Trees for Southern California

Arbor-wellness: Plan for 2020

Prevention Season is Starting

Fall & winter are the most valuable time to protect your trees from next season’s insects and diseases. Whether its sticky sap, borers and bark beetles, or diseases like anthracnose or fireblight, fall or winter are ideal times to protect your trees. When treated now, trees have all winter to move protective products into and throughout their stems, twigs and roots. These products will be ready to work as soon as new growth starts next spring. Many diseases infect as soon as leaves appear, so by NOT protecting now, we are essentially playing catch-up if we don’t protect trees until after they start growing. This also most sense, given the stresses our trees have had to overcome the past several years. Stressed trees are more prone to insects and diseases because their defense systems are weakened and they have a harder time protecting themselves. So along with proper pruning, watering and mulching, protecting against insects and diseases will help them become healthy again.

My trees seem to be struggling still, why is that? 

Well most likely they are still recovering from the stresses of the drought we have had. When trees are stressed, whether it is drought, lack of irrigation, flooding, or whatever stress has occurred, they reduce the output of new leaves and new roots. They don’t produce as much energy storage and they stop producing the compounds (auxins and enzymes) that they use to ward off attacks. Thus, they become more vulnerable to damage from insects and diseases.

Will they die? 

Its hard to determine that without a good evaluation from a certified arborist. That being said, providing extra “help” for them right now is very beneficial to their recovery. Just like a marathon runner that starts out in good shape, if that runner is forced to run back to back to back marathons without the time to recover well, they become more prone to injuries and illnesses. Allowing for proper recovery allows them to run another marathon (another stress) down the road. So, trees need this recovery period too, reduced stress from lack of water, excess heat, over watering and attacks from diseases and insects, so they can build their defense systems again, like we need to recover our immune systems.

How do I help them recover? 

First reduce additional stresses – proper watering, mulching, pruning are key components to helping your trees recover. Second, by proactively protecting a tree from insects and diseases, they have a further chance to build those defense systems. If an insect – like caterpillars for instance, defoliates a tree next spring, that tree has to put new leaves out a second time. The same goes for diseases like anthracnose or fireblight. The energy the tree expends by putting out a second set of leaves prevents it from building up its defense system again, thus prolonging the recover. If this weakened tree is subject to another multi-year drought cycle, the chance of it surviving is even lower.

When is the best time to treat my trees? 

Fall and early winter are the best times by far. This allows ample time for the systemic treatment to completely circulate throughout the tree. It allows the treatment to be ready as soon as spring growing season starts again.  Late winter and early spring are the second-best time. It is still early enough to have the treatment be effective under most circumstances.

What kinds of problems can you control proactively? 

Many of the most common insects and diseases can be suppresses this way.  Insects that produce sap, most boring insects, most scale and thrips, adelgids, caterpillars and twig boring insects for example. As far as diseases go, preventing is so valuable, because by the time you see a disease on a tree, the damage has essentially been done. This is true for fireblight, anthracnose, powdery mildew, root rots like verticillium and phythophera and stem and twig cankers and needle blights on evergreens.  Lastly a nutritional supplement can be applied at the same time. Many times, a tree is stressed in part because of the lack of available nutrients in the soil. We can provide a balanced, organic nutritional supplement that will give your trees a proper feeding. Or better yet, we can sample your soil and replace exactly what your trees need.

Fill out the form below to contact your Arborwell arborist today to help you make a tree protection plan for next year.

2020, preventative tree care, Prevention, recover, spring tree care, trees, winter

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