Some Avocado Issues
It looks extremely healthy with lots of new growth. This is the first year I have seen lots of little avocadoes – my first crop – in clusters on the tree. Recently, I have observed that some of these fruit are being eaten by something. I have seen a large grasshopper in the tree and I’m assuming this insect may be the culprit. I would like to spray the tree to prevent further mischief but would like to avoid using chemicals. Also, does the tree need to be pollinated by another avocado tree or is this an old wives’ tale?”
– Cliff Secia, Tarzana
Answer: It sounds like you have a ‘Little Cado’ (also known as ‘Wurtz’) avocado variety, since it takes around five years to produce fruit and displays a weeping growth habit. It is unlikely that you have an insect problem since avocado trees are usually not attacked by insect pests. In fact, they are considered the most carefree fruit tree, in terms of pest problems, for warm winter urban environments such as Los Angeles. Grasshoppers may occasionally munch on young avocado foliage, but they leave the fruit alone. I would guess that you have a problem with squirrels, which seem to bother most fruit crops in the Valley, or possibly with raccoons, opossums, or rats, which are also much in evidence and have been known to chew on avocado fruit in all stages of development. One remedy that you might consider is hanging mothballs from the tree, especially for nocturnal predators. The mothballs’ strong odor is said to deter foraging urban wildlife and the occasional insect pest.
Be aware, however, that mothball odor fades and you will need to hang fresh mothballs on a regular basis.
Enoz mothballs, sold at Walgreens, are a preferred brand. As a squirrel deterrent, CDs hung from tree branches are also useful.
Incidentally, a frisky pet dog or cat that freely roams your yard will also help keep unwanted animals away.
Avocado trees are self-fertile, which means a single tree will bear fruit. Where large crops are desired, such as in orchard settings, pollinator varieties are brought in to increase productivity. For example, if you plant several ‘Hass’ trees, or several ‘Little Cado’, you will notice more fruit, overall, if a ‘Fuerte’ or ‘Bacon’ variety is in the vicinity. Avocado trees are insect pollinated, primarily by honeybees but also by hover flies, which resemble small honeybees with metallic green or blue stripes on their bodies. Conditions which decrease honeybee activity, such as cold or rainy weather during flowering, will reduce pollination, resulting in a smaller crop.
Q: “We have two mature artichoke plants about four years old and three feet high. We are living in Glendale but will soon be moving to Van Nuys.
Can the plants be transplanted and, if so, when would be the best time?”
– Kerry James, Glendale
A: If you wanted to attempt this, you would need to remove as large a root ball as possible. As long as the root system remains intact within a sturdy block of soil surrounding it, transplanting should be successful. Transplanting should be done immediately following your plant’s removal from its existing location. It might also help to transport your artichoke root balls wrapped in wet burlap or in containers filled with moist peat moss.
Where leafy plants such as artichokes are concerned, it is preferable to transplant during cool weather or, in hot weather, in the late afternoon. Use a product that contains root hormone, such as Superthrive, to speed root growth and acclimation to the plant’s new location.
Q: “I have four large poinsettia plants, one of which I’ve had for more than 10 years, growing outdoors.
Three of them are dying from the tips down. I’ve tried cutting off the dead parts, but they just keep dying. I don’t see any bugs or disease on the three dying plants, but there are white spots on the leaves of the one healthier-looking plant. Since the three affected plants are in close proximity to each other, it seems like they have contracted something communicable.
They lose all the leaves/bracts on a branch and then the branch dies, most of the time. There are some new bracts and leaves growing here and there.
I am fighting rust and mildew on several rose bushes. I am using fungicide every week or two, but it doesn’t seem to improve.
Online I found the advice to remove the diseased parts of the roses, so I have been doing that almost daily. My husband thinks I am killing the roses because I remove so many leaves. What is your opinion?”
– Linda Stephens,
A: Powdery mildew, a palpable white growth typically seen on leaves, is the most common plant disease and it appears that your poinsettias and roses are victims of it. It looks like you have a serious outbreak of powdery mildew on your poinsettias, perhaps a consequence of the frequent rains and cool weather we have experienced this spring. The best treatment would be a long spell of hot and dry weather.
You are correct about the powdery mildew spreading from plant to plant.
When it rains, spores from the powdery mildew splash onto adjacent plants.
One recommended spray for prevention of powdery mildew, and rust as well, consists of one tablespoon of baking soda, one tablespoon of Ultralight horticultural oil (available at any plant nursery), and one-half teaspoon of liquid soap added to one gallon of water.
Spray in the early morning once a week. Make sure plants are well-watered a day or two prior to application and do not apply where plants are exposed to full sun or their leaves could be burned. This is usually not an issue since powdery mildew almost always occurs where inadequate sun exposure is a problem. Just to make sure that this spray formula is not injurious to your particular plant, spray a small section of your plant to see how it responds before inundating the entire specimen.
Remember: this is for fungus prevention and will do little to eliminate current mildew or rust problems.
As for plucking off your roses’ leaves, do not be concerned about regrowth since their legendary vigor will result in rapid development of new foliage.
Rockrose (Cistus species) is a Mediterranean plant that behaves like a California native and is currently in the midst of its peak bloom period. It is not dependent on summer water to thrive.
Prolific crepe textured flowers are observed in purple, orchid, salmon, or white. The foliage of some species is resinous and pleasantly aromatic and has been used for incense since ancient times
Plants tend to grow in shapely mounds. Do not be distressed if you notice dieback within a few years of planting since rockroses are not known for their longevity.