What's Best Way to Spray Vineyard on Steep Terrace?

The challenge was how to effectively spray a small vineyard on a steep slope to keep Powdery Mildew at bay. For some locations, there may be ample space during vineyard installation to terrace wide, flat rows between vines so that a tractor or other four wheeled vehicle (such as a Gator) can be loaded with a sprayer and carted between the rows. (Our property is relatively small and so we didn't terrace the land.) A simple backpack sprayer takes approximately two days and is much trouble as the liquid seems to always get clogged, and the spray in uneven. Another possibility was to purchase a motorized backpack sprayer. This would work, providing a good mist on the vines, but is heavy to carry around. Last year, Frank Bons of Sunfresh Vineyards, who operates a vineyard management company in San Diego County, sprayed the vineyard with a long hose (approximately 300 feet) connected to a large tank on his truck, first stationing the truck at the bottom of the vineyard, then driving by paved road to the back of the property. This operation took another person to manage the hose. Not all vines were reached, and a couple of sections needed to be done with a backpack sprayer. Says Frank, when it comes to spraying, "I don't like your vineyard."

As the Blue-Merle is a difficult vineyard to spray, careful attention is paid to monitoring the mildew index using the University of California, Davis system to make sure spraying is done only when absolutely necessary. Secondly, Frank suggested using a spray such as Rubigan which is effective for 14 - 21 days, depending on the weather. Frank came up with an approach that worked. He brought a 30 gallon pump on wheels to the property, hauling it to the top of the hill, connected to his 300 foot hose. (Next time, remember to drive the pump to the back gate, and lower it using 2 X 4's.) From there, he marched up and down the rows, moving the pump down the hill and across the property as required. The actual spraying operation took less than one hour. Strong pressure from the hose meant he only had to spray one side of each row.

We used 2 oz of Gowan Rubigan (Fenarimol). According to the label, the recommended dosage for wine grapes is 2 - 4 ounces per acre. We have approximately 2 acres of vines and thought we would recharge the 30 gallon sprayer once and so mixed 2 oz. of Rubigan into the machine. It ends up that we used slightly less than 30 gallons (there are approximately 1,150 vines on the property). As this was the first spraying of the season and there was no sign of mildew, Frank thinks a light spraying may have been better. Meantime, we'll continue to monitor the temperatures to keep track of the mildew pressure, preparing for another spraying later this month, using a different spray to avoid resistance buildup.

(Picture above shows grapes infected with Powdery Mildew in early June last year.)

Just Another Day in Critter Country

A bobcat walked by the door at dawn and trotted down the hill and off the property as I reached for a camera. Nice way to begin a day. Frank came over to spray the vines and as we discussed sharpshooter activity (making an executive decision to do the treatment next week to keep the bugs away) two daredevil hummingbirds split the three feet of space between us traveling so fast we couldn't see them, their sonic buzz and chirps the only evidence of their stunt. (Had the birds grown up watching movies of the pilot who flew under the Arch de Triomphe in Paris? Were these the same birds that starred in the movie Pocahontas?) We looked at each other and said, "Whoa."

The crazy lady managed to persuade the gophers on her side of the fence to infiltrate our side so I set traps as Bluey snorted among the rocks foraging for dried leaves (he thinks they're truffles). "Get over here," I called as it's warm now and they're out there. I thinned some of the strong Aglianico vines near the gopher holes and moved some 3ft. long wayward shoots inside the catch wires of the trellis system and spotted a full grown glassy wing sharpshooter and clamped fingers around it but he got away, the first one of the season. (These bugs are vectors for a disease that will kill your vines.)

I gathered up the shovel and extra gopher traps and making jingling noises as metal hit metal walked onto the path to head down the hill as Bluey led the way which he always does and I wished he'd stay behind me. Inside the squirrel hole by the path a black mass the size of large dog's turd was partially in the sun revealing a diamond pattern. I told Bluey to stay and I could only see the coiled girth of the vulnerable serpent without view of head or tail and unsure of his size. I brought Bluey back to the house and picked a weapon of choice (a metal spear) which I could thrust into the hole but the Queen was there and after explaining to her why I was putting Bluey inside she said "Don't kill it. It didn't bite you. I will go and tell it to leave."

It's her birthday and I'm trying to be nice and respectful and listen to her and tomorrow's Mother's Day and so why start a fight? I marched up to the shed to get a 32-gallon trash container which we call wine fermenters in September and a long stick to scoop up the snake and release it in the wilderness and when I got to the spot the Queen was there telling the snake not to come back. I inserted the long handle of a shovel into the hole and the reptile woke from its slumber and moved into the tunnel out of reach. Though that network of underground passageways the snake could show up anywhere. (Yes Lera, Brian, Ginny, Steve, Katie and the Earthy Woman Under The Yellow Tennis Ball this is exactly where you were walking the other week and now you see why I usually carry a shovel in the vineyard this time of year and it isn't just to cut down weeds.) Personally I don't mind snakes and we share mutual feelings towards ground squirrels and gophers but snakes and dogs don't mix.

We started working the 3rd block of 30 "sad vines" which had put out more green shoots and with the warm, longer days and cool nights everything in the vineyard is growing rapidly. To work in a vineyard is entering a time machine and two hours passed before we snapped out of our trance and noticed we were hungry so the Queen went back to the house and I went back to the squirrel hole and Mr. Snake was back again. It's the Queen's birthday and I let him be and we'll keep Bluey on a short leash.

Troubling Signs In The Vineyard: Time To Call in Disease Sleuth

Approximately 100 vines in the vineyard are showing troubling signs: dormancy; stunted growth; dried baby shoots; discolored yellowish leaves. Managing a vineyard requires being a sleuth to discern what's going on. Four cases, with accompanying photographs, are discussed below. (Click on the photos to enlarge.)

Case #1. Two blocks of 3rd leaf Petit-Sirah vines (about 50 plants) are not putting out shoots along the cordon. To paraphrase Monty Python, are they dead or just resting? It's late in the season for them not to have budbreak. At first, I thought we had burned the vines by applying too much lime sulfur mixed with organic JMS Stylet oil during their dormant spray. (Repeat, the vines were dormant, no green showing when we sprayed in winter.) Pete Anderson, who teaches vineyard management at Mira Costa Community College, assures me that is impossible. (On the other hand, in our backback sprayer the sulfur concentrates at the bottom and I'm sure these vines received an extra fortified dosage.) Pete asked me to clip the "deadwood" of the vines back to see if they are alive, and when I cut the ends of the cordon, I find that the sap is flowing. The vines seem to be alive, and shoots are coming out from the bottom of the trunks. Pete said another possibility is Pierce's Disease (PD), but to my understanding, to test for PD you need leaves, and these vines are not putting out leaves (except some new shoots at the base). At first, I didn't think PD was likely for this block, because it wasn't an area where we had seen many glassy wing sharp shooters (GWSS), which are vectors for the disease (plus, we had administered AdmirePro in the spring to ward off the GWSS). Could a pair of gophers have wiped out the vines? I began to see PD as a real possibility, so I called the San Diego County Dept. of Agriculture and left a message. My call was promptly returned (excellent customer service!) by Ms. Pat Nolan, an expert on PD whom I had heard give an engaging, authoritative lecture on PD at Mira Costa Community College last year. Ms. Nolan suggested I dig up a whole vine with roots intact so that she could run some tests to see what's bothering it. (The picture at left shows the spot where the sacrificial vine came from -- along with its colleagues down the row with no leaves). Mateo dug up the vine in protest saying it was healthy. I drove the vine down to the county office and dropped it off for Ms. Nolan's department to conduct the autopsy.

Case #2. Similar to the above, except that the vines are not dormant. They have put out shoots. However, many of the shoots have wrinkled leaves and are not vigorous. And, the leaf color is not as deep a green as healthier cousins. A whole block (30 vines of Petit-Sirah) looks similar to this. I invited Matt Hand of Southern California Entomology, a disease expert, to come and inspect. He suspects PD, but to be sure, he suggested we test it. I took leaf samples from this vine (shown at left) and brought it to the County for evaluation.

Case #3. Case three involves a row of Tempranillo vines which is the most vigorous row in the vineyard as it is at the bottom of the hill where there is actually some top soil, and, some vines may have tapped into the nutrients and moisture of the leach field. Of 25 vines in this row about 20 are impacted. The signs are little growth (which Mr. Hand calls "witchbrooming"), uneven growth (with shoots concentrated at the center of the vine and not pushing out the ends) and discoloration (which Mr. Hand calls "chlorosis"). This was an area of heavy sharpshooter concentration at the end of last year's growing season, and Mr. Hand strongly suspects PD. I'm preparing the chain saw to cut them down and a crew to dig them out and placing an order to Novavines for replacements. I sent a sample of leaves from the vine shown at left to the County for analysis, just to be sure. (PD can be transferred from an infected vine to a healthy vine by sharpshooters; hence the need to remove infected vines from the vineyard.)

Case #4 is not as clear cut. This involves the Grenache block on the opposite side of the vineyard. Very few sharpshooters have been observed in this area. Yet, to borrow a phrase from Sesame Street, "some of these vines are not like the others." The vine at left is showing slightly off colored leaves, and some very weak shoots. Could the small dead shoots be caused by too much wind? Did compost I place around the vines in Winter rob them of nitrogen? Has a dodgy gopher been attacking the vine unknown to us? Is the vine not getting enough nutrients? Concerning nutrition, it's almost time to take a petiole sample to conduct an analysis of the vine's uptake of nutrients, which is done when the grapes are "flowering." Meantime, to find out if PD could be the cause, I took a sample of leaves from this plant and sent it to the county.

So, you want to be a farmer?