- Author: Ryan Daugherty
I was dealing with a gopher problem in a lawn awhile back and I came across another turfgrass pest that you may or may not be familiar with; a chafer beetle.
These white grubs are the immature larval form of a chafer beetle.
Here in California we deal mainly with the masked chafer (Cyclocephala spp.). Mature grubs have white or cream colored, C-shaped bodies, six legs on their upper half, and a chestnut brown head. They can be confused with the somewhat smaller black turfgrass ataenius larvae (Ataenius spretulus). To identify the difference between the two, look at the tip of the abdomen (the opposite end from the head) for the arrangement of bristles and overall anatomy, we call this the raster pattern. A chafer's raster will have a transverse anal slit with an indistinct pattern of bristles all over. An ataenius will have two distinct pad-like structures on the tip of the anal slit.
The chafer grubs feed on turf roots in early spring then stop around May to pupate with adults emerging around June to mate. Adults actually have non-functional mouthparts and so do not cause feeding damage, in fact they die of starvation shortly after laying eggs. Adults are about 3/4 inches long with golden brown bodies and they emerge during the night with a strong attraction to light. If you see adults during the summer, eggs are likely being laid in your grass. Eggs hatch around August and the grubs do most of their damage in September and October before moving deeper into the soil to overwinter until the spring.
Damage looks like drought symptoms in turf: brown, blueish, or gray spots, brittle straw colored grass, thinning stands, and footprinting. These symptoms are from the extensive root feeding of the grubs as the grass loses much of its ability to take up water. You may also see vertebrate feeding from birds or skunks that can cause further damage digging for the grubs. Spots of affected turf may be small, only being a foot or two across but may combine with other spots to form large sections of damaged turf. A hallmark of grub damage is that damaged turf can be peeled back from the soil like a carpet, due to the turf having no roots.
Insect damage in home lawns is rarer than you might think, with abiotic problems like poor irrigation, mowing, or fertility practices being a more likely culprit for a struggling lawn. If there is an insect pest make sure you correctly identify the insect before intervening with any control measures. Also remember that the presence of a pest doesn't always necessitate control. A healthy lawn can withstand damage from a few grubs and a robust lawn is always the best defense against pest damage.
Damaged turf can be helped by irrigating more frequently to keep soil moist around the lawns now shallow roots. Lawn aeration can also kill segments of grub populations. Reserve any kind of chemical intervention until you see 6 or more grubs per square foot. Several insecticides are available on the market for chafers or white grub control just look at the label. UC IPM has a page dedicated to masked chafers, but keep in mind the pesticides recommended there are for professionals.
Always read and understand the label of any pesticide you intend to use. Be careful to refrain from applying insecticides (especially broad spectrum) if there are flowering plants in and around the lawn; this includes weeds like clover or dandelions as it can harm beneficial insects like pollinators that may come into contact with them.
- Author: Ryan Daugherty
It's a common frustration that anyone with a garden or landscape can relate to. I think that the temptation to apply undiluted herbicide stems from a widely held belief that the language on the label about human safety, environmental hazards, and the mixing instructions are just veiled regulatory activism designed to water down an effective product, sacrificing potency in service of some ulterior green agenda.
If you're like my friend and the conventional concerns aren't persuasive in the face of your weed woes, you may find it more persuasive (like he did) to know how declining to mix herbicides can actually make them a less effective tool in your quest for weed vengeance.
Misapplication Can Be a Waste of Your Time and Money
Herbicides can be broken up into several different categories, but two big ones are contact vs. systemic. A contact herbicide damages only the parts of the plant that it touches. Systemic herbicides translocate, meaning they move throughout the plant and poison the entire plant regardless of the point of contact.
Many well-known, home-use, brand-name weed killers sold at your garden center are systemic herbicides. When you use an excessive dose of systemic herbicide, it can damage the conductive tissue at the point of contact. This means that the material doesn't get translocated effectively and ends up working more like a contact herbicide, burning the parts of the plant it came into contact with and leaving others healthy and able to regrow. Systemics typically cost more than contact herbicides, making your cost per application higher.
Using systemics undiluted (and thus using more product) means that your cost per application is even higher than that. If you didn't mix your herbicide, you may not get the control that you need, and perhaps worse, you will have paid a premium to do it! This wastes your time and money. Don't do it to yourself. (And it's not legal and could be unsafe to you or animals.)
Microbial Breakdown
Some herbicides boast longer control for weeks or months. In the pesticide industry, this is called “residual action” or “pre-emergent action” in the weed control game: an herbicide that continues to work for a period of time after the application to ward off future weed incursions. Several things affect an herbicide's residual action, but one of the big ones is microbial breakdown.
Soil microbes are microscopic life forms like bacteria, fungi, protozoa, etc., that live in the soil. They break down all kinds of materials in the soil into their basic parts for use in their own growth and development, with different microbes being better adapted to breaking down one kind of material or another. Those materials include herbicides, which is great news because it means that herbicides don't hang around in our soils forever. However, it can be bad news when we abuse herbicides.
When we over-apply our herbicide either through dosage or application frequency, we could create a microbial imbalance in the soil. We kill some species of microbes vulnerable to the material while encouraging the population of others that are adapted to thrive on breaking down that specific material. In addition to the implications for the health of your soils, this imbalance also means that our residual herbicides are actually shorter-lived as they come into contact with a super population of soil microbes that break it down more rapidly. This is called “enhanced microbial degradation,” where pesticides are broken down more rapidly than they would be under normal conditions, even within a few hours. Like systemics, residual/pre-emergent herbicides typically come at a premium price, and your money can be wasted if your applications start becoming dinner time for a booming population of hungry microbes.
It will also mean that you won't get the longer-lasting control that you wanted and paid for, making breakout weeds and headaches more likely.
Spray Adjuvants
When you buy an herbicide, you aren't just paying for the active ingredient(s); you're also getting what they call the adjuvant package. Adjuvants are materials added to the herbicide formulation not necessarily to make the poison more poisonous, but to enhance the act of applying the herbicide itself.
If you were an herbicide manufacturer and you had a product that would work great if it didn't just bead up on the plant's surface, you would add an adjuvant to reduce the surface tension of the product. If it is too thin and runs off the plant before it can deliver the material, then there's an adjuvant for that too. Does it break down and become inert at certain soil or water pH levels? Does it gum up sprayers? Does it foam? Are the droplets too fine and prone to drift? Adjuvants have you covered. There's an adjuvant for nearly any application.
When manufacturers formulate their adjuvant packages, they do so with the assumption that you will follow the mixing instructions on the label. The adjuvants are designed to work best at the concentrations listed. Some of them are even activated by mixing them with a solvent like water or oil. If you apply the herbicide without mixing, then the active ingredient may not be delivered, or its mode of action hindered, all because you thought you knew how to use the product better than the people who designed and tested it.
Manufacturers want their products to work and to make you a satisfied customer willing to repeat your business. The label is how manufacturers communicate to their customers how to use their product for best results. When herbicides are used judiciously and responsibly, they can be powerful tools, especially when integrated with other weed management practices such as mulching, hoeing, and sensible irrigation practices. But don't skip the label!
Failure to follow label guidelines can lead to unintended consequences not just for the environment but for your busy schedule and your wallet as well.
/h3>/h3>/h3>- Author: Dustin W Blakey
Like many of you, I have been a walking sneeze these past couple weeks. There is a fair chance that I'm single-handedly keeping the antihistamine industry afloat! We're past the elms, grasses and pine pollen season so what's going on?
Although in late summer we like to blame rabbitbrush and goldenrod for our allergy woes, the most likely culprit is ragweed. With all the rain this year, the ragweed is plentiful. It thrives on disturbed ground which flooding has created more of beyond the usual roads and trails that it's usually found near. I've seen it this year in places I seldom encounter any.
Ragweeds are found across the USA, but California has its own set of species. There are several species in Inyo and Mono counties, but the one I'm seeing most right now appears to be Ambrosia anthicarpa: annual bursage.
All ragweeds are prolific pollen producers. A quick brush against them near Horton Creek covered me (and my dog) in pollen. Sneezes soon followed.
At this point, ragweed isn't really controllable. It can be managed earlier in the season with herbicides, but the plants are too far developed for that option. Even if you did manage to control yours, the immense population this year will still release enough pollen to make life difficult for another month.
My advice now is to try to avoid getting close to it and try to keep your pets out of it if they're the type that likes to snuggle up to you. If you're out hiking around and see some growing, I'd suggest moving to another spot.
- Author: Alison Collin
One of my neighbors in West Bishop noticed a pretty, white-flowered plant that had volunteered on the banks of a ditch that ran through the end of her garden. It had been identified as the extremely poisonous water hemlock, (Cicuta douglasii) and since I was unfamiliar with this particular plant I went to check it out. This is a different plant from poison hemlock (Conium) but it is just as dangerous!
The plants were about 3ft tall and the foliage was a lush green – a picture of health, and not so very different in appearance from celery, but eating this neurotoxin-loaded plant (described by the USDA as "the most violently toxic plant in North America") will cause seizures, convulsions and death as quickly as 15 minutes following consumption. Plant parts remain poisonous even when dried. This species is perennial and has large fleshy roots and although it does grow in the wild around West Bishop, and no doubt many other damp places in the area, it could pose a serious danger to children and pets if allowed to grow in our yards.
The small flowers are produced on umbel-shaped clusters (umbrella shaped), typical of the Apiaceae or Umbelliferae family of plants which is vast and varied, encompassing 434 genera and about 3,700 species and ranging from extremely poisonous plants such as hemlock to popular edibles such as carrots, celery and parsley.
If you see a plant that resembles a carrot that you can't be 100% sure you've identified it correctly, you should avoid eating it. (That is usually a good idea!)
In this case, the neighboring house also had a plant growing and the owners were unaware of it. Most likely the seed heads fall into the ditch and get distributed down-stream. This may result in it becoming more widely distributed and eventually spreading to pastureland, where it could pose a danger to livestock.
This article has information on management of water hemlock and has a convenient comparison between it and poison hemlock: https://extension.oregonstate.edu/crop-production/pastures-forages/poison-hemlock-western-waterhemlock-deadly-plants-may-be-growing .
And the fact sheet attached as a link below has extensive information about this toxic pest.
Western Waterhemlock in the Pacific Northwest
- Author: Alison Collin
Although I'm familiar with bindweed from past experience, for some reason it had never put in an appearance in my West Bishop garden until three years ago. A year after removing a lawn and having some topsoil delivered I was upset to see a small, white, Morning Glory-like flower in a raised bed in the center of my new landscape!
How could I have missed its growth up to flowering point? I regularly inspect for all the other evil weeds such as spotted spurge, yellow oxalis, yellow clover and Russian thistle, so how had this specimen avoided detection? And where had it come from? It had grown up through a patch of gaura, winding itself around several stems and the flower that I saw was just the first of many waiting to bloom.
There are two types of bindweed. Field bindweed has smaller leaves and flowers which are pink or white while Hedge bindweed has larger white trumpet-shaped flowers more like ornamental Morning Glory.
Field bindweed (Convolvulus arvensis) grows extremely fast. It has become a serious threat to agricultural crops in some areas of the country, and it is never good news in our gardens. It is a perennial weed with a very deep root system, able to penetrate as far as 16 feet below soil level! To make matters worse, the roots are soft and rather fragile. They merely break off if one tries to pull the plant up, leaving behind pieces that easily regrow. The leaves can vary from spade-shaped seed leaves to arrow-shaped on mature plants and the stems are from 1 to 4 feet in length, sprawling over flat surfaces but winding around any vertical stems or structures. The flowers produce copious amount of seed which has been known to stay viable for 50 years!
Realistically, is almost impossible to eradicate completely and the best one can hope for is to keep it under control. If seedlings are recognized and dug out before their roots have spread and before it has flowered one might eradicate it, but other methods of weed control seldom work. Covering a patch with plastic and solarizing will thwart it briefly, but will not kill deep roots, carefully hand digging out plants with as much root as possible will weaken it so long as this process is repeated whenever new growth appears. It is best to use a fork for removal because spades will inevitably cut through the roots making it difficult to get every last piece out. Likewise mechanical cultivators will chop up the roots and drag them to a new area, but for large agricultural areas there is little alternative, and so to address a heavy infestation this is done on a regular cycle as soon as any new growth emerges until the plants are weakened.
In my own garden I have removed any growth as soon as I see it. Nevertheless, shoots have appeared more than 10 feet away in two different directions from the original growth. The plant is established at the base of a young specimen maple tree, and the roots of the bindweed are beneath those of the tree, so consequently they are impossible to reach. I am sure that this is one gardening battle that I will never win, but currently I feel that I do have the upper hand.
Prevent spreading bindweed by inspecting any new plants brought in to the garden from other sources, and if you already have it don't be tempted to move plants around from one area to another, or share any garden plants with friends and spread it to their gardens! I saved a rather precious salvia by digging it up, washing and meticulously inspecting the roots for any scraps of bindweed, then planting it into a large pot where I kept it for several months before finally installing it in its new home.
For more detailed information regarding control of bindweed: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7462.html