Pest Management

This page describes how we contain pests, i.e. protect from and eradicate diseases, and protect from animals which tend to damage grape vines. 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 grape vines: . Other valuable websites are:

In addition, 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, 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 ( attached to a tractor. In the process, we cut down application times from 5 hours to 1/.2 hour!


The application of pesticides is strictly controlled in California and subject to a license from the Department of Food & Agriculture. We apply annually as a Private Applicator for an Operator Identification Number, and we submit a monthly Agricultural Pesticide Use Report to the Agricultural Commissioner within 10 days of the month following application. The license is required to purchase pesticides.

Timing of PesticideApplications.png

The best use of pesticides is as a 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 actually needed it. In the beginning, 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 ) shows the suggested timing of pesticide applications for the prevention of specific diseases depending on the development state of the vine. We are mostly 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 different diseases

Efficacy of Pesticides 1.png
Efficacy of Pesticides 2.png

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 late February before Bud Break and follow up with subsequent sprays every 2 to 3 weeks through veraison

  • 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 ) and consider bee precaution pesticide ratings ( )

  • Adjust suggested spray volumes per acre to the size of the canopy in each block (as measured by curtain-feet)

  • Enhance efficiency of application 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 shows the general properties of fungicides used in grapes

Properties of Fungicides.png

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 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 used as a curative contact fungicide for control of powdery mildew.

  • Topsin M WSB, by United Phosphorus, EPA Reg 73545-16-70506. Thiophanate-Methyl Fungicide for 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). Thus the only solution is to keep them away with a 10-foot fence surrounding the property

  • Gophers eat the roots, particularly 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.) which can do significant harm but they are less prevalent in our area. Of course, there is also highly beneficial wildlife, just to mention bees for pollination and owls which eat gophers.

The following paragraphs explain how we dealt and continued to deal with each of the 7 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 clearly a complex interplay between different practices.


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 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. Not knowing this at first we lost about 15% of all vines to gophers and needed to replant with new ones. Gophers signal where they are by leaving mounds at the end of their underground tunnels when they surface at night. To notice the mounds easily and fast it is essential to keep the ground finely tilled or evenly moved. We also planted roses at the end of each vineyard row, because of gophers like their roots even more than roots of vines. In spring we survey the vineyard every morning for new mounds, starting around the roses. When we find a mound, we try to kill them with one of the following methods

CO2 Gassing.jpg
  • Traps: Cinch Traps are the easiest and least time-consuming to deploy. Just load the trap and stick it into the hole after the mound has been swept aside. Best to do this in the early morning.This website sells traps and explains how to deploy them: .

  • CO2 gassing: Sometimes the Gophers get smart and dig around the cinch traps. When that happens repeatedly we escalate to CO2 gassing, i.e. we attach a hose to the exhaust pipe of the tractor and feed CO2 into the tunnel for 15 minutes. 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; that is after our feral barn cats had their go. 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 roots of the vines.

Ground Squirrels

Ground Squirrels.jpg

Live in nearby woods and have become a nuisance because the expand abandoned gopher burrow systems at the periphery of the vineyard. They are not a protected species, and we have been successful by spreading lethal bait around their holes (Tomcat, PCQ Ground Squirrel Bait, made by Bell Laboratories, Madison, WI). An alternative is to catch the squirrels in above ground cages; this website sells a good cage:


Rabbits invade the vineyard from surrounding fields. They are less of a problem for vines than they are for rose bushes (which help in detection of 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.


Turkeys have become a pest only since 2018 after the government decided to repopulate our area with them to enhance wildlife. They now 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 provide no benefits in the vineyard. The best way to keep them away is to use tightly woven nets.


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 lots of birds of all kind. The following section on Netting explains how we prevent them from eating the fruit.


Birds will start eating grapes as soon as they turn colour. The most effective way to prevent the birds eating the crop is to put a net over all the vines. Unfortunately, the nets would make grape thinning towards the end of veraison very difficult. So, we need to delay netting until grape thinning is completed and still keep the birds away. This, we accomplish by installing a device which produces 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 which generates distress calls of selected bird species electronically and disperses the sound over two loudspeakers on top of a high pole. The unit is powered by a car battery which in turn is trickle-fed by a solar panel on top of the pole. 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 2 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, the nets are draped 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 held away from the top of the trellising structures by metal tubes in the form of walking sticks.

Over-the-top netting.jpg

Right before picking, the detachable closing wires are dropped to the vineyard floor, and the nets are flipped on each side over the top of the canopy to provide access to the grapes. After picking 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 take around 5 hours each for 3 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 ). 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 are expected to 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.

Side Netting.png

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:

  • Pesticides holds the descriptions of the pesticides currently in use and investory

  • Adjuvants holds the descriptions of the surfactants currently in use and investory

  • SprayProgramEntry holds the contemplated entries for pesticide, adjuvant and foliar sprays planned for the upcoming growing season

  • REVIEW: SprayProgram shows the summary of all SprayProgramEntry records for the upper and lower fields in a season

  • VineyardActions is used to enter pest management activities

The screenshot below shows the “ALL: Pesticides”-layout for the pesticide Rubigan EC. The table holds information generally found on the product label. Note, we convert the standard dosage, usually given in lbs/acre, into g/curtain foot, assuming a standard 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.

ALL Pesticides.png
ALL Adjuvants.png

The next 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 spray plan, specifying 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 field and the upper field respectively. 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.

SprayProgram 2018.png

All Pest Management actions are recorded in the “ALL: 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.

ALL VineyardActions.png

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