- Author: Mark Bolda
The 2011 Annual Caneberry Meeting will be held on January 24 at the UC Cooperative Extension office in Watsonville, 1432 Freedom Blvd. The agenda is accessible through the following link:
http://ucanr.org/caneberry2011 |
- Author: Mark Bolda
by Steven Koike, UCCE
Leaf blotch disease of strawberry is being detected in some fields in coastal California this winter. Dependent on splashing water, this disease rarely occurs unless overhead sprinklers are used or rains occur. Symptoms generally consist of tan to gray leaf lesions that commonly (though not exclusively) develop along the margin or edge of the leaflets. Leaf blotches are irregular in shape and may be surrounded by a purple border. These affected areas tend to grow fairly large; they can expand and cover from 1/4 to 1/2 of the leaflet surface.
A key diagnostic feature of leaf blotch is the presence of tiny, brown to black, fungal fruiting bodies in the gray blotches. Brown to black petiole lesions can also occur. In past seasons leaf blotch has been misdiagnosed as spray burn or phytotoxicity from applied chemicals. If uncertain about the nature of such leaf symptoms, submit samples to the UC Cooperative Extension offices in the coastal counties.
Leaf blotch disease is caused by the fungus Gnomonia comari, which also has the name Zythia fragariae. Zythia fragariae survives on strawberry crop residues. The fungus does not appear to be a true soilborne fungus, so it will not likely persist in soil unless strawberry crop debris is present. The Zythia form is especially dependent on splashing water for spore dispersal and infection. This accounts for the typical appearance of leaf blotch during winter and early spring seasons when there are rains. Leaf blotch is usually considered a minor problem and fungicide treatment programs have not been developed nor are they generally recommended. The strawberry plants usually grow out of the problem. Leaf blotch spread and development is dependent on rains and splashing water, so once the winter rains cease, leaf blotch usually becomes a non-issue for growers.
- Author: Mark Bolda
It appears that there might be some confusion about a maggot that is showing up in new strawberry plantings up and down the coast of California. This maggot is the larva of the fungus gnat, a fly which commonly is found in very moist environments such as greenhouses and around potted plants indoors. The continually moist weather accompanied with the cool temperatures of late is quite likely encouraging the growth in numbers of these flies in our strawberries.
According to the UC IPM guidelines, fungus gnats are not harmful to plants and feed on organic mulch, leaf mold, compost, root hairs and fungi. They are not known to major pests of crops cultivated outdoors.
- Author: Mark Bolda
Caneberry growers in Santa Cruz and Monterey Counties are to be reminded that the threat of light brown apple moth (LBAM) has not gone away and that they should maintain or replace the pheromone based twist ties in their fields. Please bear in mind that the ties generally are effective for four months in most conditions. While the weather has become colder and there is little foliage on many blackberry and raspberry varieties, there is still LBAM moth activity on the Central Coast and fields will benefit from having mating disruption deployed.
Likewise for strawberry growers, especially organic growers, it is a very good idea to maintain or replace the twist ties in their fields going into a second year of production.
See photos below for tips on twist tie placement in the field.
- Author: Mark Bolda
One of the first posts to this blog regarded the importance of chill, both field and supplemental, to the day neutral (ie Albion, San Andreas, Portola, Monterey among others) strawberry varieties. Right now, field chill in MacDoel is in the area of 600 hours, which is plenty, even in the light of the very warm stretch of weather that took place in September. Still, be reminded that this abundance of field chill should not be considered to be a replacement for supplemental chill taking place in the cooler after the transplant has been harvested.
However, this year because of the delay in transplant harvest growers really should be striving to strike a balance between getting adequate supplemental chill to obtain good vigor and planting sufficiently early to get sufficient plant growth here in the fall. To accommodate this idea, every one of the day neutral varieties listed above can be well established with supplemental chill of 7 to 10 days, but no less. More days of chill, up to 18 days, are of course in the printed recommendations, but this year a large delay in planting may not result in acceptable plant growth and establishment.
If one follows the suggestion given above, supplemental chill will end up being on the low side, and subsequently growers must be more vigilant than usual in planting practices. Transplants must not be allowed to dry out in the field during planting, transplants should be properly placed the planting hole (no “J” rooting, and only portion of the crown above the soil line) and irrigation for establishment should keep the beds at field capacity for a few weeks.