What is in this article?:
- Grape growers looking for rain in 2012
- LBAM continues spread
- After three years of drought and two wet years — this year is shaping up to be another very dry year.
- Dry conditions look to continue and irrigation is probably a good investment right now.
- Grapes are a low-demand crop for water and nitrogen, compared to most other fruits and nuts.
LBAM continues spread
Chilling hours have been above-average and for a second year in a row, fog has been a more common occurrence as in the ”Good Old” days when the sun often disappeared for three to four weeks at a time. Chilling hours (hours below 45 F) has totaled 1044 hours at this point compared to the long term average of 778 hours (Fruit and Nut Center, UC Davis). ET of winter cover and weeds has been low. Most mornings have seen light to substantial frost, which is a little worrisome for the coming spring. But I better not say any more at this point.
During the last five years there were some scattered frost events in 2011, 2009 and 2008. Just to review last year’s reminder of comparison for soil conditions and cold, to hopefully renew the good luck:
* Firm bare ground, that is wet: +2º F
* Firm bare ground, that is dry: ---
* Freshly disked soil: -2º degrees colder
* High cover crop (24 to 30 inches): -2º to 4º (possibly 6 to 8º colder)
* Low cover crop (less than 24 inches): -1º to 3º degrees colder
* Mowed cover crop: -½º F
As spring and budbreak approach, it appears the European grapevine moth (EGVM) will be determined to be eradicated in San Joaquin County, as there were no other finds last year. Scott Hudson and his staff have done a lot of work and have been helped by all growers to speed the delisting of EGVM. That’s the good news.
The bad news is that light brown apple moth (LBAM), continues to spread and is scattered around the county. It’s still under a quarantine protocol. The other good news is, it’s easy to control. It is a Lepidoptera pest very similar to the OLR and it seems to be susceptible to the same biological control of our native beneficial insect predators and parasites. If you are within a mile of a commercial nursery you probably are in a quarantine zone. If you haven’t been contacted by the Ag Commissioner’s office, you should check.