Author Archives: Ruth

Welcome to our Demonstration Garden!

May 14, 2019

The fruit trees in the orchard this year would amaze anyone. They are striking and flush …
with pests. It’s true. Come and allow us to demonstrate all manner of pest infestation plus other unsightly disorders.

Last year was a record bounty but, this year, we are counting on one hand the number of fruits from most of the trees.

Why, on one small branch of the Mirabelle plum (photo) you can view tip dieback from brown rot, scale, aphids and leaf roller damage. The pear, just after the height of the leaf roller infestation, has now been chewed to smithereens by the California pear sawfly (photo).

Wander over to the Fuji and notice apple blister mite. Then, check out the powdery mildew on the William’s Pride.

This situation takes me back to coaching where you had to make sure you didn’t spend all of your energy on the one high-maintenance kid and take for granted the other 14 well-behaved teammates. So, yesterday, I coddled our precious persimmon. The persimmon, like the mulberry, sits and watches the devastation and only asks for a drink of water now and then. I composted-in-place its weeds, fed it some nice compost and leaf litter, and laid out a coat of chips on top. Namaste.

Sun, May 19, 2-4, Work Party
Sat, Jun 1, 10-12, Work Party
Sun, Jun 16, 2-4, Work Party
Sat, Jul 6, 10-12, Work Party

Back in February, Allison and I thought we had the winter moth larvae in check. We had banded the trunks then flattened the eggs below the band. The problem was, while we were focused down on that trunk, the winter moth larvae soon would be sailing through the air, landing on whichever fruit or nut tree was within striking distance. Much like a skilled parachutist, I think they tug a certain way on that silken thread to ensure they make it to the canopy. In April, they were landing on our sweaters and hats faster than we could squish them off the leaves and blossoms. We had kept our own trees from propagating larvae but we were defenseless against tall neighboring trees that spit out the little buggers like factories.

Yesterday, I sighed as I cleaned off more dead material from Liberty branches (photo). Oh, but then I looked closely. Was that a little speck of green? Sure enough, the tree is pushing out a new leaf where the others had been eaten.(photo) The Liberty is willing and ready to try again. OK then! We will also find energy to grow and prepare for the next obstacle.

Ruth

Plant Pathogens – Pasteurize? Sterilize? Sanitize? Boil Everything!

March 26, 2019

Recently, I was watching someone rinse a plastic polyethylene plant-potting container in a Brown Rotbleach solution for reuse. I was pretty sure that pot needed to be thoroughly rinsed of organic matter prior to the bleach rinse.

The observation made me think of several reasons why a gardener needs to know how kill plant pathogenic microbes, e.g., effectiveness of our thermal composting process, best product to spray on our pruning shears or, preparation of a previously purposed plastic pot for propagation.

I tried and failed to make a helpful chart. It proved far too difficult, due to so many factors to consider:

varied expressions of quantities
different types of substrates and their porosity
amount of contact time needed
type of organism and state of organism
health hazards
the level of disinfectant desired
shelf life of product
humidity in relation to temperature
corrosiveness
cost of product
where the organism lies and whether you can even get at the bugger

Method

 

Botrytis cinerea (gray mold-fungal) Nectria galligena (apple canker) Weed seed

(sow thistle)

Verticillium dahliae (Verticillium wilt)

 

Pseudomonas syringae pv. tomato (Bacterial speck)
0°F yawn
165°F Dead 1 hr Dead 1 hr
5% sodium hypochlorite (bleach) sol. 2g/liter 20 hr LD90
4%v/v iso. alcohol effective
.3% iodine solution 93% dead 93% dead
Quaternary ammonium 4g/liter 20 hr LD90

Heat destroys microbes best and heat with humidity is even better. However, except during our thermal composting process, heating to 149F for two hours is not practical. As such, I tried to get some answers about products that are available and familiar.

Sat, Apr 6, 10-12, Work Party
Sun Apr 21, 2-4, Work Party
Sat May 4, 10-12, Work Party
Sun May 19, 2-4, Work Party

Let’s start with bleach. Sodium hypochlorite is very reactive, affected by surface contamination from organic matter and it’s irritating to use. It’s difficult to know what dose to use and, at the concentrations that many people use, it leaves a residue on the surface. (1000 ppm will destroy all microbial pathogens but for the tough resting spores. Using household bleach (5.25% sodium hypochlorite), the dilution would be 1:50 or 5T per gallon.)

Ethanol (think Everclear) can kill most organisms but it is highly flammable and evaporates quickly. It dries out the organism (which is why the similar product, isopropyl alcohol, is better as a disinfectant for the skin). Alcohols reportedly won’t kill some spores and they harden rubber and some plastics on tools.

I could not get a clear idea whether hydrogen peroxide is a good pathogen hunter. Articles refer to its effectiveness, especially on inanimate surfaces, but indicate that hydrogen dioxide is a superior disinfectant on plant production surfaces.

Quaternary ammonium chloride. Hmm. There is a lot of controversy about Quats and they are reported to be not always effective against the tough customer – the fungal resting spores.

This brings me to a possible unsung hero – iodine. Remember when you went camping where the water was bad. You mixed the two tablets in water and waited. That second tablet helps with the discoloring and the taste and also is a solubilizing agent. One potential downside is shelf life – about five years.

A flameless loop sterilizer might be the ultimate tool but not readily available and you would need a power source. (We will leave out solarization, which, for the time being anyway, might be challenging in Western Washington.)

This study is way more complex that I could have ever imagined. There is no one size fits all solution. Shown here is a popular chart from two State of Washington professors (who are also fine authors of plant pathology books).

Good reads:
Investigation on the fungitoxic effect of an iodine solution on three plant pathogens in vitro. Bengt Boysen.
Bachelor project in the Danish-Swedish Horticulture programme
2004-1 (ISSN 1652-1579)

Time and Temperature Requirements for Weed Seed Thermal Death
Ruth M. Dahlquist, Timothy S. Prather, and James J. Stapleton
Weed Science 2007 55:619–625

Soil Solarization and Thermal Death: A Logarithmic Relationship Between Time and Temperature for Four Soilborne Plant Pathogens.
G.S. Pullman, J.E. DeVay and R.H. Garber
American Phytopathological Society, Vol 71, No. 9, 1981 p 959

Temperatures Necessary to Kill Fungi in Wood
USDA Technical Note 259, Forest Products Lab Feb 1956

Safe Procurement and Production Manual A Systems Approach for the Production of Healthy Nursery Stock
Griesbach J., Parke, J.L., Oregon Association of Nurseries, January 2012
https://www.researchgate.net/publication/282649506

Dose Curves of Disinfectants Applied to Plant Production Surfaces to Control Botrytis cinerea
W.E. Copes, Plant Disease-American Phytopathological Society, May 2004

Chemical Disinfectants
https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html

Quaternary Ammonium Compounds
Quaternary ammonium compounds are the most commonly employed broad-spectrum hard surface disinfectants employed in animal research facilities.
From: Laboratory Animal Medicine (Third Edition), 2015
https://www.sciencedirect.com/topics/neuroscience/quaternary-ammonium-compounds

EPA Hard Surface Disinfectants
https://www.education.nh.gov/instruction/school_health/documents/disinfectants.pdf

Ruth

Get To The Root Of The Matter

February 4, 2019

Last week Sue helped us plan the vegetables for the year. We were thinking of what to plant near the far north olla and we got out our photos of plant root lengths from the summer.

The olla best serves a plant with a deeper root system. (See Water Conservation page on Ollas.) We decided peas would be a good choice.

The plants can teach us so much. We dig up some of the roots to assess for health and to measure length.

Sat, Feb 16, 1-3, Pruning Class
Sun Feb 17, 2-4, Work Party
Sun Mar 17, 2-4, Work Party
Fri Apr 12, 10-12, Fig Pruning

We got a surprise in October when we pulled out the cucumbers and peppers that were planted near an olla. Carefully, we used the hori hori and excavated around the base of the olla to see which plants took advantage of the water. A small fig tree, planted about 10 feet from the olla, had wrapped its roots tightly around the brown water vessel. And Nancy wondered why her little fig didn’t need any water during the dry months!

Now we know that root pruning is another task for the winter to-do list. Check your own garden bed sites to see if any plants may be robbing water from your edibles.

Here is a good chart on root depth per plant (page 1). Following that is an interesting chart on the water needed to provide certain nutrition parameters by crop.

 

 

 

 

 

 

 

Last week, three of us heard our State Climatologist Nick Bond speak. Nick is still delivering the same message; in general, western Washington is in for dryer summers and wetter winters. In addition to being water efficient, the more water we can collect during the winter the more we will have in the summer.

We are lucky to have our cisterns and, if we had one more, we could make it through the summer. Last year we used our 4,000 gallons from our cisterns plus 1,300 from the City water supply.

We will continue to explore ways to increase water efficiency. Check out the recent addition to the Perforated Pipe Page.

Ruth