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Tuesday, September 6, 2016

Sunflower Oozing From Damaged Area

Q. At one of the schools I have a garden club at there is a sunflower that has oozing coming out on stem. I think it is sweet because the wasps love it. Looks like slim flux.  Any ideas what it is? 



A. I am not a pathologist or entomologist but maybe this is bacterial stem rot which could make a yeasty smell in any sap coming out. It could possibly be stem borer but I think stem rot makes more sense to me.
            Cut it open and see if you see a “worm” inside the stem. If you do, it is stem borer.
            Smell the liquid coming from the damaged area that attracts wasps and see if it smells “yeasty”. If it does, then it is probably Erwinia (bacterial) stem rot. Anyway, this bacterial disease should have a foul smell if you get your nose right up to it. Plant diseases don’t hurt animals do it won't harm you.

In any case, you can wait and let the seeds mature for eating or planting and get rid of it OR get rid of it now. If this is bacterial stem rot it can spread from plant to plant through open wounds and spread by insects. Pruning of infected plants followed by pruning of uninfected plants can transmit this disease from plant to plant. Dont water these plants with splashing water from a hose or hose end sprayer. Sanitation is very important.

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Sunday, September 4, 2016

Leaves on My Apricots Are Drying Up

Q. I have a three-year-old apricot tree in the southeast part of Las Vegas. For some reason, the leaves have dried up (have the consistency of potato chips) and it appears to be dying. It gets watered daily at 3:00 am for 2.5 hours with drip irrigation at 8 gallons per hour. 

A. The problem may be daily watering if there is poor drainage. If this is the problem, you should be able to push on the tree and see if the bottom is loose in the soil or if the tree is very firmly anchored and does not move.
            If the base of the trunk moves as if it is not firmly anchored then this is a root problem due to, most likely, watering too often. If the soil is continuously wet it can promote root diseases that favor very wet soils and tree roots that are weakened due to suffocation.
            I would try to water every other to every third day but give it more water when you do. You can give it more water by adding a couple more emitters.
            Another method is to put some vertical holes in the soil about two feet from the trunk to a depth of about two feet and backfilling these holes with gravel to improve drainage. This is called vertical mulching. You can use a posthole digger for this.
            If this is not the case, then look at more exotic possibilities such as weed killers applied to the soil or drifting into your yard from your neighbor.

Irrigation Water Can Direct Where Tree Roots Grow

Q. I just planted a white fruit mulberry tree at my house and close to the street. It is away from my front door or walls about 20-30 feet and it is 5 feet away from the water meter. Am I okay?  By the way, this tree is a fighter. I transported it once, almost lost it, and it came back to life after dying or shedding its leaves.
Mixture of black and white mulberry fruit in Afghanistan
A. You should be okay if you make sure that no water is leaking from the meter or anywhere you do not want the roots to go. The roots are extremely invasive.
            Make sure you apply irrigation water to areas AWAY from places you want to keep the roots from going. Roots will grow where there is water and nutrients. They don’t go “looking for water”.
            Remember, if you are focusing on harvesting the fruit you will prune it differently than a shade tree. If you want to feed the birds, then let it grow as a shade tree.

How To Get Rid of Palm Seedlings

Q. I have 100's of palm seedlings coming up in my yard. Can you tell me the best way to get rid of them, short of pulling them up by hand, which for me would be physically impossible! I’m 88 years old.
Palm seeds are released in abundance from Washingtonia fan palms. These seeds are nearly 100% germination. They will land in shrub beds and even come up through mulch.
When you try to pull them when they are very young and in dry soil they frequently break off.
But when you pull them when they are a bit larger and the soil is wet they will frequently pull out with their entire root system.
A. I am sure there are probably some weed killers that will kill palm seedlings but those weed killers would not be safe around other landscape plants. I have had no luck killing them with Roundup even at the highest rate.
            I understand your dilemma in pulling them but If you pull them when they are about 12 inches tall and the soil is wet they should pull out fairly easily including the roots. If you try to pull them when they are small or cut them off they may regrow.
            I know this may be a lot of work but if you use a shovel in wet soil and just push the shovel in three or 4 inches a couple of inches from the Palm seedling you can pop them out of the ground pretty easily.
            If you are to use chemicals, a.k.a. weed killers or herbicides, then you would select something that kills woody plants and spray them individually so that the chemical does not harm other plants.

If you are going to use a weed killer, pick one that kills woody plants but apply it with a spray bottle, wedding only the leaves and not the soil. These types of weed killers can damage other woody plants in the landscape including trees, shrubs and fruit trees.

Keeping Worm Bin in the Desert

Q. Do you keep your worm bin in the house or outside? If outside how big is it and do you have to do anything to keep it cool? Could you do a post about how you care for your worms? 
We bought to Rubbermaid plastic storage containers for the worms. I drilled 3/8 inch holes all through the top, the upper edge of the side and the bottom for drainage and air movement. I used the dark one because I didn't want light inside of it.

The side of the container was drilled with the same size holes for ventilation. I didn't want to drill holes all through the sides because I was worried about the worms.

Drilling holes in the bottom of the container was very important for draining water. I tried to put holes in places on the bottom where water could drain easily. I didn't want the holes to close because I was worried about ruining the integrity of the container.

I bought 1 pound of red wigglers because I had read they were some of the more adaptable of the warms. In the summer I kept the container outside on the east side of my home under the shade of a sweet Acacia.
A. I bought two Rubbermaid plastic storage containers from a local box store and drilled holes through them for ventilation and drainage. I was worried about the temperatures, both our hot summer temperatures and cold winter temperatures and keeping the compost too wet. 

The summer temperatures can get over 110° F frequently and approach 120° F (50C). I didn't want direct sunlight on the storage containers with worms because of the heat created from direct sunlight. I place them outside in the shade of a suite Acacia tree on the east side of my home on top of rock mulch. 

I was hoping the HOA would not bother me about it and they didn't. I started the worms off with a 2 inch layer of shredded paper from a shredder. I mixed vegetable scraps, that I normally would throw out, with this shredded paper. 

By the way, I do not use colored paper or colored ink, only white paper with black ink. The ink was soy-based and not lead-based and from a printer and newspaper. I threw in a couple cups of soil with this mix. I always blend my vegetable scraps in the blender, including coffee grounds and egg shells, just to get them as small as possible before giving it to the worm bed. 

Once the mixture inside the container looked inviting and thoroughly moist, I put in a pound of red wigglers compost worms. I bought them online when the temperatures were cool and they all survived the UPS shipment just fine. They loved it! I covered this worm bed with cardboard that I kept wet. They had no trouble with the heat during the summer as long as they were kept wet. I didn't risk them outside during the winter because our temperatures can dip into the low 20s late at night. Sometimes even colder than that. So from mid December until February 1 they stayed in the garage. They handled the garage temperatures just fine.

I had one problem once when the worms were attacked by an insect. I was not in the country. My daughter told me about it and when I returned a couple of weeks later they were all dead. I never identified the insect but they could fly according to my daughter. 

I thoroughly cleaned out the vermicompost and used it. I sanitized the plastic container. I started the process all over again. During the summer months I would have to add water with a spray bottle about every other day until I saw some water coming out of the bottom holes. Then I stopped adding water. 

I always kept the cardboard moist on the bottom. It would dry out on the upper surface. I would lift the cardboard and add the slurry of vegetable scraps from my blender to the surface of the worm bed. They were very active after a feeding. 

Once they degraded the food in the worm bed, I would add food only on one side of the container. This would get them to migrate towards the food and I could clean out some of the finished vermicompost and add fresh shredded paper bedding to the side that was cleaned out.

Why Is Our Saguaro Cactus Leaning?

Q. We got your email from our son in law who recommended www contact you. We have a saguaro the has been in place for 10 years or so. A couple of months ago, it started leaning and now is in danger of falling over. We staked it but are not sure what to do.  We were told it might be rotting from below although it looks ok. It is about 6 1/2 feet from the pool but there doesn’t seem to be any water near it.  I am attaching a couple of pictures. We would appreciate any advice or insight you can give us.
A. The usual reason that saguaro might lean are related to water. If the plants are getting water too often then this can cause root death due to suffocation. Roots are important for anchoring the plant in the soil and they might lean with root damage.
            I would not water more often than once every three weeks if you are giving it lots of water each time. If you are very, very careful you might get away watering more often but with less water but the water needs to be applied up to at least three feet from the trunk.
            Also, if water is applied close to the trunk and the soil is dry outside of this area then roots develop close to the trunk but no further out. As the plant gets tall and “top heavy” the roots do not provide enough anchorage, they are not spread out enough, and the plant begins to lean.
            While you are staking it, add more emitters further from the trunk to encourage the roots to spread. They should be about 18 to 24 inches apart to provide even coverage of water to the soil. I couldn’t tell from you picture but the second option looks more likely with what I could see in the picture.

Worms on Palo Verde More Nuisance Than Threat

Q. These are the worms we find on our Palo Verde tree in the backyard. We would like to get rid of them but do not know how. Is there something besides spraying the whole tree which is huge, a systemic maybe, that would do the trick and not kill the tree. They make a mess of the sidewalk and other stuff under the tree.  Any help would be appreciated. 

Worms or caterpillars on readers Palo Verde
A. These critters have been reported elsewhere in the desert Southwest. Must be because of our wet spring weather. They should disappear in a matter of a week or two or less. It is a larva or caterpillar of a moth. I am not sure which one.
            Some caterpillars fold or roll leaves together with silk to form shelters. Others feed on leaves beneath a canopy of silk, sometimes creating "nests" in foliage, and others devour entire leaves along with stems.
            Your tree can get a lot of damage from these critters and still be fine. If there is enough of them you should see a lot of their poop on the ground because they eat a lot, voraciously, before they pupate and begin the change into a moth.
            You can spray with an organic pesticide such as BT or Spinosad but as far along as they are I think it's a waste of money. Even if they defoliate the tree it will relief again and come back out.
            Relax and have a glass of lemonade but don't put your lemonade under the tree.

Avoid Bird Damage - Pick Fruit Early

Q. I had a lot of bird damage in my apricots this year.
Stark Saturn donut peach and bird damage. The birds love this fruit. It develops very high sugar content in the desert.
A. The bird damage should be easy to correct if you harvest the fruit when it is still hard but has some color development. Keep an eye on the fruit and look for early bird damage. If the fruit has begun to change color, you can harvest when they are hard.

Early producing apricots are less hard hit than the later ones.
            Apricots develop the same sugar content as when it is left on the tree. Remember that sugar content does not equal flavor. Flavor is much more complex than just sugar content. It has a lot to do with the mixture of different chemicals inside the fruit such as the organic acids, flavonoids, etc.

Vermicompost and Insect Control



Q. I have read that worm castings can be effective in eliminating aphid and white fly infestations. Is it effective on all insects that suck plant juices? What effect do worm castings have on beneficial insects? Are there any special instructions or precautions to be considered when using worm castings around fruit and vegetable plants? 

Our own red wrigglers at work in a custom vermicompost bin
A. You are one up on me on this topic. I have not seen any scientific publications that document this to be true in a general sense. If there are some, I would love to see them. 

There is some work at Ohio State University that showed fewer insect problems on vegetables growing on vermicompost than without it. They focused on something the earthworms left behind called chitinase.


There is some grant money right now for researchers working in this area. There are a lot of unanswered questions like how long can you use it, what does the quality need to be, how much do you need to apply and others. 


There is no argument that vermicompost is a great soil amendment and may reduce the need for synthetic pesticide applications. There is some debate about “chitinase” and its effect on some insects. I think you have to be careful about jumping to conclusions on this one.
            If chitinase is effective on insects it will be nondiscriminatory. In other words, it does not know the difference between a good insect and a bad insect.
            Once leaf hoppers have matured and they are hopping around a lot when you pass by them they are difficult to control without conventional "hard" pesticides. I have never heard of worm castings used for anything but a fertilizer. That information about is new to me.
            About the only organic method I know of that does a pretty good job controlling leaf hoppers is Spinosad. However, Spinosad has to be applied when leaf hoppers are immature in the nymph stages. It never totally eliminates them but reduces their numbers considerably if they are applied early enough and the sprays are directed where they are living.
            As an example I have used Spinosad sprays in about May on grapes to reduce leaf hopper numbers. I apply the spray about one week apart for 2 to 3 applications as soon as I see the nymphs on the undersides of leaves.
            I direct the spray upward so that the bottoms of the leaves are covered and then I repeat the spray on the tops of the leaves as well. To my knowledge worm castings have no effect on any kind of insect pests or beneficials. Treat it just as you would compost.