When Daryl Salm returned from vacation March 18 to his Soledad, Calif., office there was a dusting of snow in the foothills ringing the Salinas Valley.
Two weeks later the weather was in an early summer pattern: morning fog and afternoon winds.
On top of that, bud break is about two weeks late in Monterey County this year where Salm oversees about 3,000 acres of vines as viticulturist for Valley Farm Management and his boss, Richard Smith's Paraiso Springs Vineyards, Soledad, Calif.
The weather is “scattering” early season powdery mildew protection applications. “Elevation is making a lot of difference this year. We are treating part of a vineyard one day and coming back in three weeks to treat the other half — both on the same ranch,” he said.
Also on the weather front, Salm said chilling has been adequate, but winter rainfall has been in very short supply, less than half of normal so far. “We'll be turning on the drip systems fairly quick this year,” he added. Although there was some spring frost in the southern end of the valley, Salm has not seen any frost-damaged buds in his vineyards.
Powdery mildew is the biggest pest for coastal vineyard managers to challenge, but Salm has his share of insects to monitor.
“We treated for leafhopper and are seeing orange populations building to threshold levels,” he said. Typically associated with causing bunch rot problems, orange tortrix can also cause damage early.
It's the same kind of damage in coastal vineyards as the omnivorous leafroller in inland areas. Overwintering larvae feed on any soft, exposed vine tissue, weeds, and in grape mummies on the vine. Spring feeding is on buds, canes and webbed leaves. If not controlled, larvae enter bunches and make webbing nests among the berries. Their feeding on berries allows entry of bunch rot disease organisms.
Salm said when the early-season bud throws its scales, the orange tortrix can chew a small hole in the bud and destroy it.
Salm and Smith manage vineyards with an IPM approach, opting for less disruptive pesticides and the use of cover crops for habitat for beneficials and vertical canopy management to reduce pests and provide better spray coverage.
Like many coastal vineyardists, Smith and Salm have trained their vineyard workers to be observers for not only pest, but beneficials as well.
Taking mites as an example, Salm said, “We have trained our people to scout for predatory mites as well as damaging two-spotted and Pacific mites. If we see high numbers of predatory mites, we'll be much slower to spray.”
Mites are not a major problem for Salm's vineyards and are generally localized. “Over the years we have learned where the hot spots may be and look there first each year, looking for yellowing, leaf cupping and chlorophyll loss on basal leaves.
“Over the years, we have had very limited mite infestations,” he said. “When we do treat, we go back to the same area the next year to make sure we got a good kill the year before.”
Salm uses Agri-Mek, first registered for use on grapes, in 1999, for early-season mite control up until last June. “I was familiar with the miticide because I had used it on strawberries in the past and was confident it would control mites in grapes without doing too much damage to the beneficial insects.”