Late Blight of Tomato and Potato Webinar

What late blight looks like.

What late blight looks like.

Got late blight? Learn more about this pathogen, which caused the Irish potato famines, by joining a free webinar at eOrganic on January 14, 2014 at 2PM Eastern Time (1PM Central, 12PM Mountain, 11AM Pacific Time). The webinar is free and open to the public, and advanced registration is required. Attendees will be able to type in questions for the speakers.

Register now at:
https://www1.gotomeeting.com/register/601056184

The webinar will feature five plant pathologists. I’ve always found these webinars to be informative even for the home gardener.

A Hinged Cover for a Raised Bed Vegetable Garden

hinged raised vegetable bed

What’s another way of describing a raised bed vegetable garden? How about “feral cat litter pan,” “Skunk feeding troth,” or “Dog exercise pen?”

The solution to these problems? Netting or row cover. The problem is that vegetables need a lot of tending so you’re always pulling off and on the cover. And, inevitably, you forget to put it back on one evening and that’s the night a skunk goes on a grub hunting party.

This year I decided to create a hinged cover for one of my raised beds so that I can easily access vegetables without having to remove the bird netting or row cover each time I want to access the bed. I’ve found that I can remove the netting once the vegetables have matured.

To create the cover I made a frame with some 2 x 2 inch lumber and bent some electrical conduit pipe (and a piece of leftover copper pipe) for the hoops.  I put some gate hinges on the back, stood back and named my creation: Vegetable Guantanamo.

How To Stop Powdery Mildew

powdery mildew

My winter squash has what Mud Baron once described as “jock itch for plants:” powdery mildew. I’ve tried all kinds of notions and potions in the past, but this year I decided to see what the science says about powdery mildew. Our climate where I live in Los Angeles is, unfortunately, ideal for producing this vexing fungus.

IPM
Let’s begin with some condensed advice from UC Davis’ Integrated Pest Management page:

Preventative measures:

  • grow resistant varieties
  • find a sunnier spot for the vegetable garden
  • back off on nitrogen

Non-chemical approaches

  • sprinkle plants with water mid morning–add soap for more effectiveness
  • remove infected leaves promptly and dispose of them

Fungicides:

  • apply horticultural oil, neem oil or jojoba oil if the temperature is under 90° F. Do not apply any of these oils if you have used sulfur.

DIY Options
For home remedies I turned to advice from Washington State University horticulturalist Linda Chalker-Scott.

How about milk, widely touted as a powdery mildew treatment? According to Chalker-Scott the answer is yes it might work, but you may need to apply milk before powdery mildew appears. And the studies were done with whole milk, so the effectiveness of other kinds of milk have not been tested. Milk has not worked for me in the past, probably because I applied it too late.

How about baking soda? Chalker-Scott is skeptical. Baking soda has never worked for me.

Compost tea? I hate to bring it up as the topic is insanely controversial. I discovered a tempest in a compost tea pot when I tried to write a non-partisan magazine article about it. Let’s just say I ended up leaning towards the skeptical side when I looked at the evidence. Let me know if you think I’m wrong on this, especially if you can leave a link to a peer reviewed study.

Conclusions
What has definitely worked for me in the past is seeking out resistant varieties. I wasn’t smart enough to remember this fact so I’m going to try the soapy water approach and step up to something stronger if I have to. Part of my problem might also be too much nitrogen–my infected squash is in our straw bale garden and I had to apply a lot of blood meal to get it going. More sun would also help but that would involve cutting down a very large tree. I’ll update this post later in the season.

Let’s hear from you . . .
What powdery mildew treatment have you tried and how did it work? Leave a comment and join the conversation!

And I put the question out on the Root Simple twitter feed and got a few divergent opinions:

Christopher Kennedy ‏@ckpfunk Bonide’s Copper Fungicide for organic gardening. I spray every 14 days this time of year instead of every other w/ baking soda.

Alec ‏@Alec I’ve tried horsetail tea, sea-crop, baking soda, compost tea, and neem oil on mildew, but none compare to milk.

Alissa Walker ‏@gelatobaby I just sprayed with a baking soda solution seems to have done the trick so far. And removed all damaged leaves.

Alex Mitchell ‏@alexmitchelleg give the plants some air, water the ground not the leaves. Could spray diluted milk with water on leaves – never worked for me

Hens in the Orchard for Pest Control

hensinorchard

Photo: hencam.com

Author Terry Golson, who blogs at HenCam.com, sent along a great pest control tip in response to our thrip post–chickens, of course!

Chickens and orchards go together like gin and tonic. The hens take care of pests, clean up rotten fruit, add nitrogen to the soil and the canopy of the orchard protects the hens from hawks and heat. Plus you get eggs and meat. Permaculture in action.

The 1920s era photo you see above comes from one of Terry’s posts, Chickens in Orchards.

How to Deal With Thrips on Stone Fruit

thrip damage on nectarine

Research hint: when you have a pest problem on an edible plant, Google the name of the plant and “UC Davis.” What comes up is UC Davis’ handy Integrated Pest Management info sheets, evidenced based information on all kinds of problems. This is how I figured out that a small insect called the western flower thrip (Frankliniella occidentalis), was noshing on our nectarines.

Thrips damage the fruit when it is small. The scars enlarge as the fruit matures.

How do you manage thrips? UC Davis notes:

Western flower thrips overwinter as adults in weeds, grasses, alfalfa, and other hosts, either in the orchard floor or nearby. In early spring, if overwintering sites are disturbed or dry up, thrips migrate to flowering trees and plants and deposit eggs in the tender portions of the host plant, e.g. shoots, buds, and flower parts.

Thrips are often attracted to weeds blooming on the orchard floor. To prevent driving thrips into the trees, do not disc the cover crop when trees are in bloom. Open, weedy land adjacent to orchards should be disced as early as possible to prevent thrips development and migration of adults into orchards.

It was an exceptionally dry year which may have contributed to our thrip problem.  And perhaps some mulch and weeding around the base of the tree is in order. UC Davis goes on to suggest monitoring methods as well as organic controls if that’s your cup of tea.

The scarred fruit gets rotten on the tree and is unappetizing. We did get some unblemished fruit, but there was enough of a thrip problem to warrant monitoring next year.

Did you have thrip problems this season?