Saturday, January 15, 2011

Dormant spray recommendations.

Always read and follow label instructions!
For the products we sell, mix together in each gallon of spray:
2 oz LiquiCop (= 4 Tbsp)
2.5 – 3.5 oz spray oil
(= 5 – 7 Tbsp, or 1/8 to <1/4 cup)

You can use a hose-end sprayer** if you use the lower amount of oil (you will barely add any water to the concentrated mixture). Otherwise, use a tank sprayer.
Spray the tree thoroughly, to the point of runoff.
It will probably take about two gallons of spray to cover a medium-size tree with conventional training and pruning; one gallon of spray to cover a summer-pruned backyard orchard tree.
Spray peaches and nectarines while they are still dormant.
You can spray other fruit trees such as apricots. plums, and cherries with the same mixture.
Many fruit species such as figs, persimmons, and pomegranates need no spraying. Citrus are sprayed only as needed for specific pest and disease problems.
Dormant and bloom sprays don’t control the worms that get into apples and pears, or the new fruit-fly larvae that are attacking cherries. For those we use growing-season sprays.

The diseases we are concerned about are:
• peach leaf curl, which only affects peaches and nectarines. Sprays are only effective before the buds break. If they show color (green or pink) it is too late.
• brown rot, which primarily affects apricot (and almond) blossoms. See note*. Sprays are only effective when the trees are in bud and bloom. Plums and cherries, as well as peaches and nectarines, can also get brown rot, but it is much less common.
• This spray mixture also helps control shothole fungus, and the oil helps to reduce over-wintering insects.

MicroCop (copper sulfate) and Polysul (lime sulfur) are no longer available, so we are now recommending the liquid copper spray. It is less effective for leaf curl, unfortunately, but easier to apply. The problem is that the final spray solution, following label rates, is lower concentration than you were applying before. We cannot recommend that you exceed the label rates.

** You cannot apply both products at the same time in a Dial-A-Pro hose-end sprayer. Apply each at the label rate, 24 hours apart.
* Copper is not effective for brown rot on apricots, and there is no organic or low-toxicity alternative available to homeowners. Chlorothalonil is available, but is very toxic; read and follow label instructions carefully if you choose to use it. Note non-chemical suggestions for control measures at
Prompt removal and destruction of fruit mummies and diseased plant parts prevents the buildup of brown rot inoculum and helps keep rot below damaging levels. Prune trees to allow good ventilation. Furrow irrigate or use low-angle sprinklers to avoid wetting blossoms, foliage, and fruit. Plant varieties that are least susceptible.

Product information:


Spray Oil

draft Jan 14 2011

Tuesday, January 11, 2011

Read and follow label instructions!

Read and follow label instructions.
This is an important phrase! It affects the safety and effectiveness of the products you use. Failure to read and follow label instructions can injure or kill you or others, lead to plant burn, harm beneficial insects and wildlife.
What exactly does it mean? How do we intepret the labels on pesticides?

Signal Word.
Any pesticide, organic or otherwise, is labeled with one of the following words:
Those are in increasing levels of toxicity: Caution products are the lowest toxicity, Danger are the highest. The toxicity is based on direct harm the pesticide may cause by swallowing it, inhaling it, getting it on your skin, or getting it in your eyes. Tests are done to determine how lethal it is and how likely to cause skin or eye irritation.
Different products with the same active ingredient may have different Signal Words due to differing dilution rates of the concentrated or mixed solutions.

Precautionary Statements
These give you a guide as to what makes a particular pesticide dangerous to you or others. It may be swallowing or inhaling the pesticide, absorbing it through the skin or eyes, or direct irritation from contact with the concentrate or mixed spray.

Personal Protective Equipment (PPE):
The label will tell you which protective clothing or gear to wear, how long you, children and pets need to stay out of the treated area. Most people fail to heed this, but it is key to protecting yourself and others from harm.

Environmental Hazards
The label will state whether it is toxic to wildlife. Unfortunately, the impact on bees is not always mentioned. The likelihood of drift, runoff, leaching, and groundwater contamination may be mentioned. These are technical terms that you should understand before you apply the product.

Active ingredient
You may not recognize the name, because a chemical may be better known by its trade name. Example: Daconil is the trade name of chlorothalonil. Manufacturers do not have to disclose the inert ingredients, but do have to list their percentage.

California’s Prop 61 requirement:
If an ingredient in the product, active or otherwise, is “known to the state of California to cause cancer” that must be on the label. It's up to you as to whether that matters to you.

Storage and Disposal
There are general instructions for how to dispose of partially used or empty pesticide containers. Where do you keep your pesticides?

What if you lost the label?
Nearly every company now puts pdf copies of their product labels online. Hey, you can increase the font size and actually read it!

Do organic pest control products have the same labeling?
Yes. Anything that is sold as a pesticide in California has to be labeled. Organic pesticides aren’t necessarily safer than conventional ones.

Here is an example of a commonly used home garden fungicide:

Active ingredient: chlorothalonil 29.6%” You may know this as Daconil, a trade name.
Known to the State of California to cause cancer.
Signal Word: “Warning.” Red flag. This is one of the more toxic products homeowners can buy. I always urge purchase and use of a Caution labeled product if possible.

Precautionary Statements: “May be fatal if inhaled. Harmful if swallowed or absorbed through skin. Causes moderate eye irritation. Avoid contact with eyes, skin or clothing. Do not breathe spray mist. Prolonged or frequently repeated skin contact may cause allergic reaction in some individuals.”
Now we know where the Warning label comes from. Given these specific warnings and that higher-toxicity Signal Word, it is important to use the exact protective equipment listed.

PPE: The following are required: long-sleeved shirt, long pants, shoes and socks, protective eyewear, specific types of waterproof gloves, an approved respirator with an organic vapor cartridge or canister with a specific type of filter. You should not even open the bottle until you are wearing all of these listed items.
“Keep children and pets off treated area until dry.” The sprayed material on the leaves can poison them.

Environmental Hazards: Chlorothalonil can kill aquatic invertebrates and wildlife, can drift to nearby water, can runoff into surface water for “several days or weeks after application.” It can leach into groundwater, even when used according to the label.

Directions for Use: These give specific rates of application for certain pests on certain types of plants, by name. The rates are not the same for every crop. Do not exceed them, as they are based on tested effectiveness and are the basis for how toxic the product is considered to be. In some cases they will tell you a maximum amount you can use per year.
The Preharvest Interval (PHI) tells you how many days before harvest you can apply it. These vary by crop (14 days for onions, 7 days for cabbage, day of harvest for carrots), so you need to check the label carefully.
“Avoid spraying plants during extremely hot and sunny weather.” This is because chlorothalonil, like many pesticides, can burn the foliage during hot weather. “Do not apply … within one week … of oil or an oil-based pesticide.” Same issue: you may burn the leaves when used in combination with oil.

Storage and Disposal: These don’t vary much from one product to another, but it is wise to read them. In particular, disposal of the empty container has specific requirements. When you use the last of the bottle, rinse it three times and pour the rinse water into the spray tank. Then puncture the bottle (to prevent re-use) and dispose of it according to local regulations. If you don’t know what those are, contact your local agricultural commissioner.

For some discussion of a new product for vegetables and fruit trees, here is a previous blog article:

Wednesday, January 5, 2011

In Memoriam: Dan Pratt

I am sorry to report that Sacramento-area nurseryman and garden media personality Dan Pratt died December 25 at the age of 78. Pratt succumbed to injuries from a fall, after a series of illnesses over the last several months.

Employed by Capital Nursery for 24 years, he was heard locally on KFBK (originally KGNR) radio with his Garden Doctor program, which ran for 19 years: first from 9 to 11 a.m. on Saturdays, and then from 8 to 10 on Sunday mornings. For more than 20 years he wrote a weekly column about garden pests for the Sacramento Bee (What’s Bugging You?) and made frequent appearances on local television. His annual garden calendar was sold at garden centers throughout Northern California.

Pratt gave many talks over the years to garden clubs around the Sacramento Valley. He was active in the local chapter of the California Association of Nurseries and Garden Centers, serving as president twice and on the board of directors for several years. Dan led garden tours of Britain and other regions. After his retirement he moved back to his family’s property in Napa.
He leaves a son and daughter and longtime girlfriend. A private burial service has been held.

That all sounds very dry. I considered Dan a friend for over 25 years, having met him when I first got involved in our local chapter of the nursery association. He was always full of ideas, present at nearly every nursery event we worked on, and enthusiastically promoted gardening and the nursery industry. Dan introduced me to radio work and graciously allowed me to host his show when he traveled. After retirement, he and Jo stopped by my shop any time they were passing by Davis, to swap stories and tell jokes. He liked good food, cruises, and terrible puns.

Dan Pratt was a great friend of gardens, gardeners, and garden centers everywhere.

Addendum: from the Sacramento Bee Jan 7 2011