Pest Monitoring and Scouting in grapes

Introduction An ecological approach to managing pests in agricultural crops is known as Integrated Pest Management (IPM). IPM involves compiling detailed and timely information about a crop and its pests to ensure that pest management decisions are economically, environmentally, and socially sound. IPM requires a more tolerant approach to pest control than traditional insecticide-based programs. Timely monitoring provides accurate information that allows the correct control decisions to be taken.

Importance of Monitoring in grapes At the farm level, first activity is gathering information about the environment, pest, potential biological control agents and the crop. This activity is termed scouting, or monitoring, and is performed frequently during the growing season to acquire periodic information about the vineyard pest status so that timely decisions can be made and actions can be taken if necessary. Monitoring is the most fundamental, yet the most often neglected activity in an IPM program. Both the need for control and the effectiveness of any action taken are determined by monitoring pest and natural enemy populations.

Best approaches to scouting: Why scout vineyards? • Provides early detection of pests • Reduce risk of pest outbreaks • Information on other vineyard issues • Improve timing of sprays • Identify hot-spots Best approaches to scouting: Regular weekly scouting Sample multiple vines on border and interior e.g. 100 vines per vineyard (100 across 4 rows) Return to same vineyards each week Randomize the position of the samples Keep clear records of what you find

Monitor the vineyards- “ Scouting” Which of the expected pests are in your field? Know both “what” and “how many” by properly sampling the field? Compare the sample count of pests to “ economic threshold” or “action threshold” to determine if action is necessary. An economic threshold is the Pest population level or extent of crop damage at which the value of the crop destroyed exceeds the cost of controlling the pest.

Establish Monitoring sites for pest Place monitoring stations near woodlots and inside vineyards (2 in each position) Check at weekly intervals during growing season.

Key Insect and diseases Pests to monitor for… Stem borer Stem girdler Thrips Flea beetle Mealybugs Helicoverpa Spodoptera Mites Downey mildew Powdery mildew Anthracnose Black rot

Basic IPM- Monitoring / Scouting Weather data Pest type and number Monitor/ scout vine orchard Select management option Pheromone trap data Pesticide selection & time of spray Biological control Mechanical control Cultural practices., etc. Other trap data

Monitoring tools 1. Pheromone traps: For moths (i.e Helicoverpa, Spodoptera) Artificial lures have been developed based on the specific sex pheromone that the female of each species uses to lure males for mating. Pheromone traps using these lures and a sticky coating are a quick and convenient way to monitor the populations of such pests. Traps are placed in the vineyard before the beginning of moth emergence. 2. Light trap Light traps make use of a light source to attract night-flying insects. They are especially useful to monitor certain species of moths. 3. Yellow sticky trap Yellow sticky traps are efficient to monitor population densities of day-flying insects that respond to the yellow color.

Disease Calendar Disease Bud break Pre- bloom Bloom 1ST Post bloom Cluster closing Veraision Harvest Leaf drop Black rot ++ ++++ +++ + Powdery mildew Downey mildew Anthracnose +++++ +, ++, +++ denotes fungal activity +++++ denotes appropriate time to spray Source:www.dpi.nsw.gov.au

Some examples…. Grape leafhopper: Overwinters near vineyards and moves to grapes in late May-June. Sampling must be done on underside of leaves Grape flea beetle is easily spotted on vines and buds on sunny days. Scouting should be done around the edges of vineyard first, where it enters from nearby woodlots. Threshold: 4% bud damage/sq. m

Let’s sum up Monitoring and Scouting for insect pests is an important strategy of an IPM Regular scouting is necessary to detect early infestations and also monitor the efficacy of control measures. A crop scouting program includes both visual inspection and through tools like traps. Scouting should be done once a week. This information forms a sound basis for decision making- the absence of this information usually leads to overuse of pesticides.