- Author: Paula Pashby
I have a potted Meyer lemon tree (Citrus Meyer) that I have regrettably neglected these past few months. I recently took some time to give it some tender loving care and was relieved to discover that my tree was doing well and even sprouted some new growth. On closer examination, I noticed that the newly discovered shoots looked quite different from the rest of the lemon tree. The main lemon tree has medium-sized, oblong-shaped leaves, whereas the new growth has small, three-lobed, narrow leaves.
So, I had to ask myself - should I keep this new growth? And the answer turned out to be a gigantic NO! I learned that the new growth must be removed in order to keep the integrity of the current tree, because the new growth could possibly take over the original tree and likely not produce decent fruit. The reason it is unlikely to produce good-quality fruit is that it is a “graft rootstock sprout”, a product of citrus tree grafting.
The grafting process is a technique used to grow the best possible fruit tree by joining parts from two or more plants to create one new hardy plant or tree. Grafting is accomplished by binding a scion (upper part of plant) selected for its desirable fruit, with a root stock (bottom part of plant) selected for its strong root system.
With my Meyer lemon tree, I discovered that often times the graft rootstock is taken from a completely different type of citrus tree, called Trifoliate orange. Trifoliate orange is a preferred rootstock because it is cold and drought tolerant, and very strong and hardy. But you wouldn't want the full tree, as it is known to produce very sour fruit that can be rather inedible unless cooked.
I thanked the Trifoliate orange portion of tree graft for providing the lemon tree with such a strong root system, and then using a disinfected pair of clippers, I carefully removed the graft rootstock sprouts. I made sure to cut close to the main tree but leave enough room for the wound to heal. The Meyer lemon tree is feeling loved again.
![Trifoliate orange, with fruit by Martin LaBar is licensed under CC BY-NC 2.0. Trifoliate orange, with fruit by Martin LaBar is licensed under CC BY-NC 2.0.](/blogs/blogcore/blogfiles/108493.jpg)
- Author: Christian Jordan
Shasta College will host a Geographic Information Systems (GIS) for Forest Resilience workshop this October. The course has been developed with industry partners and will provide practical, applied experience in the use of GIS to support project management for forest and wildfire resilience. The workshop will take place on four consecutive Saturdays, beginning October 5th. The attached flier includes further details. For additional information or questions, please reach out to Dan Scollon: dscollon@shastacollege.edu.
SC24 4695 GIS Forest Resilience Course Flyer PRINT
- Author: Bob Niklewicz, MG at the Fuller Park Rose Garden
We had a tremendous amount of heat in July and August. Many of our bushes suffered greatly from heat stress. Leaves turned brown, looked wilted and/or just fell off to preserve the moisture in the bush. Extra watering or, better yet, more frequent watering to keep the root ball moist is like CPR.
Leaves will also turn yellow from the heat or be susceptible to black spots. Pick those off the branches and off the surrounding ground to reduce the fungus from spreading. Remember to sterilize your pruners after each bush to reduce the spread of the black spots. Note: We are not totally past severely hot days this summer; protect your roses. Even putting a cover/shade or umbrella over them during the hottest part of the day will save them from the worst part of the heat.
You may also see aphids now. For the majority of cases, just using a high pressure hose spray will wash off those soft bodied pests. Do it every couple of days until the problem is reduced greatly or cleared. Also, make sure your irrigation systems is working correctly so that your plants receive proper moisture.
Rose of the Month: Angel Face
Remember when pruning: Toss plant debris into your city compost bin and not your own compost pile. The Napa City compost center produces higher temperatures to destroy the spores while your backyard pile will not do so. When it comes time to add mulch, consider getting it from the Napa recycling center.
If you have questions about the Fuller Park Rose Garden and the Master Gardeners (MGs) who maintain the rose garden, we are usually in the garden the first Sunday and third Thursday of each month between 10:00 and 12:00, weather permitting.
You can also go to our Master Gardner website: napamg.ucanr.edu for more details.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
- Author: Kathy Keatley Garvey
A praying mantis, Stagmomantis limbata, stretches beneath a Mexican sunflower, Tithonia rotundifola, in a Vacaville garden.
Ms. Mantis: (Startled to see she is not alone) "Well, hello, there! How are ya? I'm just dropping by to say Hello!"
Photographer: "So, this is a meet-and-greet? And not a meet-and-eat?"
Ms. Mantis: "Exactly. I'm not interested in eating bees or butterflies. Ooh, there goes a honey bee! Ooh, there's a long-horned bee! Omigosh, a butterfly!"
Photographer: "You're just looking?"
Ms. Mantis: "No, just stretching. See, I've closed my spiked forelegs."
Photographer: "Then why did you move beneath the blossom?"
Ms. Mantis: "For the shade. Yes, that's it. For the shade."
Photographer: "Sounds pretty shady to me. Just admit it, you're hungry."
Ms. Mantis: "Well, now that you mention it, I guess I could use a bite to eat. Just a little bite...a little bee...a little butterfly..."
Photographer: "A quick bite?"
Ms. Mantis: "Lightning fast! One-twentieth of a second! Now, if you'll excuse me..."
The camera clicks. The mantis vanishes...along with an unsuspecting bee.
![A praying mantis, Stagmomantis limbata, stretches beneath a Mexican sunflower, Tithonia rotundifola, in a Vacaville garden. (Photo by Kathy Keatley Garvey) A praying mantis, Stagmomantis limbata, stretches beneath a Mexican sunflower, Tithonia rotundifola, in a Vacaville garden. (Photo by Kathy Keatley Garvey)](/blogs/blogcore/blogfiles/108479.jpg)
- Author: Thomas J Getts
I have gotten quite a few calls about blister beetles this year. There was a newspaper article up in Modoc that caused some stir, and was picked up by a lot of social media pages. So, what are blister beetles and why do we care?
Blister beetles get their name for a reason. They contain the toxin cantharidin, which can be excreted when they are threatened, or crushed which causes bad blisters on the skin. While this is problematic they typically are not drawn to humans, and blisters can be avoided by not handling them. Where they pose a larger problem is as a contaminant of hay, where they can be crushed/killed and incorporated into a bale posing as a potential toxin to be consumed by livestock.
Photo One: Blister Beetle on Musk Thistle next to a Roadway
Let's take a step back. What are blister beetles and why are they a subject of conversation now? There are numerous native blister beetles in California. Some are striped, some are brightly colored, but most of the ones I have been seeing are black or grey. The immature larvae of blister beetles feed on the eggs of grasshoppers or ground dwelling bees. I don't have to tell anyone in the Intermountain region, we have had quite a few bad grasshopper years which has led to an increase in blister beetle populations. Typically, the adults lay eggs right on top of the egg beds of grasshoppers. I'd be on the lookout for blister beetles the rest of this year, and definitely next year as they feast on the eggs underground. (So, they are not all bad as they kill some hoppers!).
Photo Two: Grasshoppers flying away from an ATV in a pasture up in Modoc County
As adults, they can consume forage, but typically they are drawn to flowers and consume pollen. (Different species have different preferences.) I have mainly seen them on roadsides, trail sides, and rangelands where there are flowering plants. In hay fields I have only seen them in “native hay pastures” that have wildflowers. However I have gotten reports of them being on the edges of some alfalfa fields that have started to go to bloom.
For livestock generally they are only problematic when they get caught up in a bale. How many is too many? This is a good question. Numerous extension publications cite research done back in the 80's looking at how many blister beetles it would take to kill a horse (horses are more susceptible to the toxin than cattle of sheep). As with all toxin's it often depends on numerous factors, and there is not a single number of beetles that will kill a horse every time. The amount of toxin per beetle can vary by species of beetle as well as within species of beetle. From the research done in the 80's the cantharidin content per beetle ranges from 0.5mg to 5mg, and is toxic to horses at the tune of 1mg/kg. This means that there can be a huge range of how many beetles it will take to kill a horse (see table one). With that being said while it may take a significant number of beetles to kill a horse, as few as five beetles can start to cause colic.
Table one: Adapted from Capinera et al. 1985. J. Econ. Entomol. 78:1052-55.
So, what do you do about the beetles? One of the best things to do is scout fields before they are cut to make sure you do not have them in the field. While it might be counter your management objectives to maximize yield during the mid-season cuttings, cutting alfalfa or clover before bloom can reduce the incentive of beetles to move into hay fields. It is also important the keep a clean hay field, and reduce the number of weeds that may flower in the field drawing the beetles in. There are insecticides like (Sevin- carbaryl, or Warrior- lambda-cyhalothrin) which are effective at killing blister beetles in forages, but may pose their own drawbacks. While most of the beetles should die and fall down to the ground after an insecticide application, there is still some potential for them to be incorporated into the hay during the cutting and raking process. Likewise, the pre harvest intervals for these materials can delay cutting and could require driving over a lot of hay, if an aerial applicator is not available. Cutting around infested patches or isolating/discarding hay that may be contaminated, could be a prudent strategy. Likewise waiting until the beetles move out of the field could be an option.
Photo Three: Blister beetles on clover in a "native" hay meadow in the Intermountian region
There are over 300 species of blister beetles in North America, and not all have been tested for their Cantharidin content. When haying especially using modern equipment with conditioners, I urge you to be cautious, and take time to scout fields before cutting, especially if that hay is going to the horse market.
For more information there are some excellent extension publications online from UCIPM, Colorado State University and North Dakota State.
Photo Five: Blister Beetle on Feral Rye next to the Susan River in Lassen County