Pest Management

This page describes how we contain pests, i.e., protect from and eradicate diseases and protect from animals that tend to damage grapevines. The best starting point for any farmer in California is the website managed by the University of California on Integrated Pest Management. Here is the link to the section covering grapevines: http://ipm.ucanr.edu/PMG/selectnewpest.grapes.html. Other valuable websites are:

The listing of other Pest Management Websites: http://ipm.ucanr.edu/GENERAL/links.html
The U.S. National Pesticide Information Center: http://npic.orst.edu/NPRO/
The California Dept of Pesticide Regulation: https://www.cdpr.ca.gov/docs/label/labelque.htm
The EPA Pesticide Product and Label System: https://iaspub.epa.gov/apex/pesticides/f?p=PPLS:1
The OMRI database of organic products: https://www.omri.org/omri-lists

Also, the TTU Vineyard Advisor application from the Texas Tech University is a handy tool for mobile devices. It can be downloaded free from the Apple Store or the Google Play store

Because there is so much good and well-organized information about pest management readily available on the web, we concentrate here on the practical aspects and what we do about:

Pesticide Sprays: what we spray and how
Animal Control: how we keep damaging vertebrates out of the vineyard.
Netting: how we protect the maturing grapes from birds and yellow jackets
Data Management: how we record what we do

Pesticide Spray

In the beginning, we used to spray with a manually operated back sprayer, then we switched to a tank with a pump and long hose, and finally, we graduated to a Gearmore Venturi Air sprayer (http://www.gearmore.com/gearmore/orderportal/catalog_presentation/by_group/0/163/0/0/0/0/0) attached to a tractor. In the process, we cut down application times from 5 hours to half an hour!

The California Department of Food & Agriculture strictly controls the application of pesticides and requires an application license. This license is required to purchase pesticides. We apply annually as a Private Applicator for an Operator Identification Number. After each application, we submit an Agricultural Pesticide Use Report on the Agricultural Commissioner’s website

The best use of pesticides is preventative; once a disease has infected a vineyard, only eradicants can help, and they tend to be less wholesome. Prevention is like paying insurance premiums; if you don’t get hit by a disease, you never know whether you needed it. In the early 2000s, we sprayed aggressively; then we relaxed and got hit by mildew and canker diseases. So now, we are more diligent and spray following an annual program, keep better records and, when possible, use organic products.

The table on the right (from the IPM website http://ipm.ucanr.edu/PMG/r302902111.html#EFFICACYCONV ) shows the suggested timing of pesticide applications for the prevention of specific diseases depending on the development stage of the vine. We are primarily concerned with Powdery Mildew, Dead Arm, and Eutypa Dieback. The following two tables (from the same website) show the efficacy of different commercially available pesticides against various diseases.

Our spray program is still evolving as we only started to rationalize our approach in late 2018; before, we sprayed by the seats of our pants more or less following external advice or reacting to infestations.

Our current guidelines are:

Start with a dormant spray in mid-February and follow up, after Bud Break, with subsequent sprays every 2 to 3 weeks through Veraison
We prefer natural/biological products over chemical products (see tables above)
Alternate among products with different modes of action (FRAC#) to reduce the chance of buildup of natural resistance (see table below)
Follow best practices for protecting bees (see http://ipm.ucanr.edu/mitigation/protect_bees.html ) and consider bee precaution pesticide ratings (https://www2.ipm.ucanr.edu/beeprecaution/ )
Adjust suggested spray volumes per acre to the size of the canopy in each block (as measured by curtain feet)
Enhance the efficiency of the applications with adjuvants where recommended (Adjuvant is a broad term describing any additive to a spray tank that enhances pesticide activity. Examples of adjuvants are surfactants, spreader stickers, crop oils, anti-foaming materials, buffering agents, and compatibility agents).
Combine Pesticide spray with Nutrient/Foliar spray when required
Establish a baseline “Spray Program” each winter and adjust it according to weather conditions and field observation during the season.

The following screenshot of the website http://ipm.ucanr.edu/PMG/r302900211.html shows the general properties of fungicides used in grapes

The Spray Program for 2018 is described in the Data Management section below.

In the past, we rotated through the following pesticides to prevent a range of diseases and a buildup of resilience (i.e., different FRAC numbers).

Champ by Agtrol, US94.023.04. Copper hydroxide flowable agricultural fungicide to prevent powdery & downy mildew. 1-2.5 pts/acre
Thiolux by Syngenta EPA Reg. No 100-1138. Dry flowable micronized sulfur to control powdery mildew and but-l, blister- & red spider- mite.
Microthiol by United Phosphorus EPA Reg No 70508-187. Micronized wettable sulfur to control blister, bud & red spider mites, phomopsis, and powdery mildew 3-10 lbs/acre
Rally 40WSP by Dow AgroSciences, EPA Reg no. 46719-410pp. Myclobutanil soluble powder is used to prevent antinacnose, black rot, and powdery mildew.
Rubigan EC by Dow AgroSciences, EPA Reg No 62719-134. Systemic fungicide to control powdery mildew.
Pristine by BASF, EPA No. 7969-199. Fungicide to target angular leaf spot, anthracnose, black & ripe rot, downey & powdery mildew, leaf blight, and phomopsis.
Stylet-Oil by JMS FlowerFarms, EPA Reg No.65564-1. Paraffin oil for control of fungal diseases, aphid-transmitted plant viruses, and phytophagous insects and mites.
Kaligreen by Otsuka Agritechno, EPA Reg No.70231-1. Potassium Bicarbonate soluble powder is used as a curative contact fungicide for the control of powdery mildew.
Topsin M WSB, by United Phosphorus, EPA Reg 73545-16-70506. Thiophanate-Methyl Fungicide for the control of Botrytis and Eutypa.

At times we add the following surfactants (except with Kaligreen and Stylet-Oil):

No Foam B by Creative Marketing Research, CA Reg No. 1070775-50008-AA. Surfactant blend to act as spreader-activator & buffer.
Vintre by Oro Agri, CA Reg. No. 72662-50004-AA, a surfactant to improve distribution and efficacy of miticides & fungicides.

Animal Control

Wildlife is adorable, but it can interfere with agriculture. We are concerned with the following vertebrate pests:

Deer eat the foliage of vines and thus kill the plants top down. They are protected in our area (i.e., illegal to shoot). Therefore the only solution is to keep them away with a 10-foot fence surrounding the property
Gophers eat the roots, particularly roots of young vines, and are thus particularly harmful in new plantings – they kill the vines bottom up. They are hard to detect because they live underground in extensive burrow systems
Ground Squirrels can damage vines by eating the bark of established vines, and they dig extensive burrow systems, particularly at the perimeter of vineyards. They also expand abandoned gopher holes
Rabbits eat the foliage of young vines but, given their reach, are only harmful in very young plantings. Their burrows, however, can be destructive.
Wild Turkeys have recently been introduced in our area to add more diversity to the wildlife. They can be very destructive due to their size; they disrupt the ground cover and damage the canopy.
Yellow Jackets have become a recent nuisance. They slice open maturing berries and suck out the sweet juice.
Birds eat the almost-ripe berries before they are ready to pick and thus must be kept away late in the season

There are other animals (voles, wild pigs, etc.) that can do significant harm, but they are less prevalent in our area. Of course, there is also highly beneficial wildlife, to mention bees for pollination and owls, which eat gophers.

The following paragraphs explain how we deal with each of the seven pests mentioned above. Note, certain vineyard practices mentioned earlier (like planting roses at row ends for early detection of mildew and planting cover crops for soil maintenance) attract these pests; there is a complex interplay between different practices.

Deer

Deer presented a significant problem during the early years until we secured the property by a 10-foot fence and discouraged them from revisiting their old habitat by crashing through the fence.

Gophers

Gophers continue to be our biggest constant challenge as surrounding fields are their natural habitat, and they cannot be fenced out. They are hard to detect and harmful because they live underground and eat the roots of living plants. Early on, we lost about 15% of all vines to gophers and needed to replant with new ones. Gophers signal their location; they leave mounds at the end of the tunnels they burrow at night. We keep the ground finely tilled or evenly mowed to notice the mounds quickly. We also planted roses at the end of each vineyard row because gophers like their roots even more than vines’ roots. In spring, we survey the vineyard every morning for new mounds, starting around the roses. When we find a mound, we try to kill the gophers with one of the following methods

Traps: Cinch Traps are the easiest and least time-consuming to deploy. Just set the trap and stick it into the cleared hole. Best to do this in the early morning. This website sells traps and explains how to deploy them: http://www.gopherslimited.com/index.html.
CO2 gassing: Sometimes, the Gophers get smart and dig around the cinch traps. When that happens repeatedly, we escalate to CO2 gassing. We attach a hose to the exhaust pipe of a combustion engine and feed CO2 into the tunnel for 15 minutes. The picture on the right shows the use of a small tractor for this purpose. An alternative is to use a special-purpose engine, as we explain below. The problem with this method is there is no immediately visible proof of success.
Detonation: when neither Cinch Traps nor gassing works, we escalate, as a last resort, to blowing up the gopher tunnels with a “Varmit Getter Original.” The contraption mixes propane with oxygen and injects a small amount of the mixture into the gopher tunnel, and then ignites the tunnel remotely..

We catch 50-100 gophers each season. It is essential to keep the gopher population under control; otherwise, they dig extensive tunnel systems and become harder to catch before they eat the vines’ roots

Ground Squirrels

Ground squirrels live in nearby woods and have become a nuisance because they expand abandoned gopher burrow systems at the periphery of the vineyard. We used to spread lethal bait around their holes (Tomcat, PCQ Ground Squirrel Bait, made by Bell Laboratories, Madison, WI). However, these baits are problematic because the animals that eat the dead squirrels might get poisoned as well. Consequently, we have switched to CO2 gassing with a special-purpose engine made by BurrowRX: http://www.burrowrx.com/. An alternative is to catch the squirrels in above ground cages; this website sells a good cage: http://www.gopherslimited.com/index.html

Rabbits

Rabbits invade the vineyard from surrounding fields. They are less of a problem for vines than they are for rose bushes (which help detect mildew). We have not been very successful in trapping them, so we tend to fumigate their nest at the periphery of the vineyard with CO2 from the tractors or with the BorrowRX unit.

Turkeys

Turkeys have become a pest only since 2018 after the government decided to repopulate our area to enhance wildlife. They appear in spring in large flocks (often 20+) and stay through autumn before the hunting season. Because of their size and lack of familiarity with vineyards, they can be very destructive to trellises and fences – they also pick maturing grapes right through the nets. We have not yet found a legal way to get rid of them.

Yellow Jackets

Wasps, and particularly Yellow Jackets, have become an increasing nuisance. They are attracted by the high sugar content during the final maturation period and slice the grape skins. While bees help in the pollination, Yellow Jackets don’t, and they provide no benefits in the vineyard. The best way to keep them away is to use tightly-woven nets.

Birds

Birds represent a significant challenge shortly before harvest – they devour grapes after Veraison when their sugar content rises. We are located in an area with a wide range of trees and bushes attracting many birds of all kinds. The following section on Netting explains how we prevent them from eating the fruit.

Netting

Birds will start eating grapes as soon as they turn color at Veraison. You can either scare the birds away or shield the grapes with netting. We first tried to scare them away but were not very successful, so we resorted to nets.

The most effective way to prevent the birds from eating the crop is to put a net over all the vines. However, nets significantly complicate grape thinning and testing after Veraison. We can delay netting until grape thinning is completed and keep the birds away temporarily. We can accomplish this by installing a device producing bird distress calls – effectively fooling the birds into believing that their brethren in the vineyard are in distress and it’s better to stay away. We use a BirdBard Pro Plus Combo purchased from JWB Marketing (see suppliers). It’s a unit that generates distress calls of selected bird species electronically and disperses the sound over two loudspeakers on top of a high pole. The device is powered by a car battery which in turn is trickle-fed by a solar panel. We initially thought this would be enough of a bird deterrent eliminating the need for netting. Unfortunately, the birds learn that they are being fooled, and when the vineyard is in an area with a dense bird population – like where we are – their learning curve is fast, and the fake distress calls cease to be effective after a few weeks. This is still long enough to wait with netting until the Veraison is complete.

We used woven nylon netting Bare-Hand Flex Bird Nets from Plantra, Inc (651) 686-6688, which is 17 feet wide and comes in 1250 foot rolls. The nets are cut to the lengths of the vineyard rows and stored during the year in plastic containers.

Right after grape thinning, we draped the nets over the top of the dual canopies with a netting applicator attached to the back of a tractor. Then the nets are closed under the vines with two detachable wires hooked to the trellising trunks and held together with hog clips. The nets are kept away from the top of the trellising structures by metal tubes in the form of walking sticks.

Right before picking, we used to flip the nets on each side over the top of the canopy to provide access to the grapes. After harvest, the nets are removed by reversing the application process – i.e., by pulling the nets off the canopy with the help of the netting applicator. Net application and net removal, in the lower field alone, used to take around 5 hours each for three people: one person driving the tractor, one person in the netting applicator, and one person on the opposite side of the row.

In 2016 we started replacing the seasonal draped-over-the-top nets described above with permanently installed side-nets (Permanets from SpecTrellising https://www.spectrellising.com/ ). These nets are more expensive and tedious to install at the outset, particularly on quadrilateral cordons. But they have significant advantages:

They take only minutes to put up or take down (vs. hours with traditional nets)
They should last longer (10 years vs. 3-5 years)
They have a finer mesh which not only keeps birds out but also wasps
They can easily be removed temporarily to take grape samples in the final weeks of maturation.

The following graphic illustrates the switch from Over-the-top Nets to Side Nets.

Time will tell how long they last and whether they are worth the installation effort.

Data Management

Data management for pest control involves the following tables and layouts:

“ALL: Pesticides”-layout holds the descriptions of the pesticides currently in use and inventory
“ALL: Adjuvants”-layout holds the descriptions of the surfactants currently in use and inventory
“ALL: SprayProgramEntry”-layout holds the contemplated entries for pesticide, adjuvant and foliar sprays planned for the upcoming growing season
“REVIEW: SprayProgram”-layout shows the summary of all SprayProgramEntry records for the upper and lower fields in a season
“INPUT: VineyardActions”-layout is used to enter pest management activities

The screenshot on the right shows the “ALL: Pesticides”-Layout for the pesticide Rubigan EC. The table holds information generally found on the product label. We convert the standard dosage, usually given in lbs/acre, into g/curtain foot, assuming a typical vineyard has 6000 feet of canopy per acre. Our lower vineyard with the quadrilateral trellis has 8,300 feet of curtain, or canopy, per acre. Our upper vineyard with the bilateral trellis has 4,800 feet of curtain per acre. In our view, curtain feet are a better measure for the amount of vegetation to be protected than acreage. Further note that the table also contains the critical FRAC numbers and directions for spray applications.

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The following screenshot shows the “ALL: Adjuvants”-Layout for Vintre, a surfactant used in combination with pesticides and nutrient sprays. Surfactants improve the effectiveness of sprays by breaking down the surface tension in the spray droplets and thus improving the contact and adherence to the leaves. The dosage is given in grams per gallon of spray volume.

At the beginning of each season, we set up a spray plan. It specifies when which pesticide, adjuvant and foliar spray will likely be used and in what amount. Entries to this spray program are made in the “ALL: SprayProgramEntry” layout, which has a record for each spray action in the lower and upper fields. This screenshot shows the record for spraying a combination of Microthiol and LIG-Calcium in the upper field on April 28, 2018.

The following screenshot of the layout “REVIEW: Spray Program” shows how we combined pesticide, surfactants, and foliar sprays in 2018. Each line in the tables represents one Spray Program Entry.

All Pest Management actions are recorded in the “INPUT: VineyardActions”-Layout. The following screenshot shows the Microthiol + LIG-Trace application on May 23, 2018. We sprayed 800 g of Microthiol and 600g of LIG-Trace with 27 gallons of purified water in the upper field.

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Last updated: May7, 2021