Chapter 20

Integrated Pest Management

Monitoring for Crops Pests

Monitoring (scouting) is a basic component of integrated pest management (IPM) programs. Monitoring is the regular inspection of grapevine pests, including insects, pathogens, nematodes, and weeds. Monitoring includes the following: (1) making accurate identifications of pests and related crop injury present in the vineyard; (2) determining the abundance of the pest populations; (3) recording crop stage and management practices; and (4) carefully recording all vineyard observations. Monitoring provides many advantages. It serves as an early warning system for the presence of pests and diseases. This allows for the implementation of appropriate pest control strategies before pest populations and diseases escalate. Furthermore, regular monitoring allows for the evaluation of pest management control actions, including the use of natural enemies.

Visual Observation

Visual observation can be useful to determine the presence of pests. The most common way to determine if pests are present is to search for the presence of pests on leaves, stems, or other plant parts. This strategy is best for aphids, spider mites, some psyllids, and other arthropods that do not fly readily when the plant part (or sampling unit) is counted or removed. This method can also be used for immature stages of pests, such as immature whiteflies. Visual observation can be very subjective, so it’s important that the same person monitors the crop throughout the season.

Scouting Frequency

Vineyard scouting must be scheduled such that increases in pest populations are detected as soon as economic thresholds are reached. Some crops need to be monitored at weekly intervals, if not more often, until there is no longer a serious threat of pests, at which time scouting frequency can be relaxed.

Scouting Patterns

Before a scout enters a vineyard an appropriate route must be planned. For efficiency sake, an M-shaped walking pattern is best used on square or rectangular shaped vineyards. In irregularly shaped vineyards scouts must keep in mind that they must cover a representative area of the vineyard. For example, you cannot scout one edge of the vineyard and expect pest populations to be the same in other areas.

Pest Sampling Techniques

Various pest sampling techniques are used to monitor pests in the vineyard. The type of technique selected will largely depend on the potential pest complex of the plants to be protected. Some pests are somewhat universal and can be monitored using conventional methods such as sticky traps or visual observation of plant parts.

Beating Tray

A beating tray is held horizontally just beneath plant foliage, and the foliage above is struck sharply a standard number of times (2 to 5) with a short stick or shaken. Arthropods falling to the tray are immediately counted and then shaken off.

Sweep Net

An insect sweep net is useful to estimate pest and beneficial populations (See Figure 20.1). In using a sweep net, develop a uniform sampling technique, which permits comparisons among samples on different dates. Each sweep sample may cover an arc of 180 degree or 90 degree (straight sweep), with the net striking the upper 6 to 8 inches (15 to 20 cm) of the plant. Samples are taken at numerous locations within the vineyard.

Pheromone Traps

Insects secrete pheromones to alert other insects about information such as the sex of the insect, trail location, alarm, and grouping. Synthetically produced pheromones mimic the chemicals produced by insects and are used to lure specific insect species to specially-designed traps (See Figure 20.2).

Sticky Traps

Sticky traps are efficient and important monitoring tools that can alert growers to the early presence of pests, indicate hot spots and insect migration patterns, and provide other information that can be used in control strategies (See Figure 20.3). Sticky traps are useful for monitoring blue-green sharpshooter movement in the vineyard.

Phenology Calendars and Growing Degree-Day Models

Phenology calendars and growing degree-day models are knowledge based tools that IPM practitioners can use for monitoring pest development and properly timing control tactics. Both of these tools help account for the annual variability in pest development, which can vary two to three weeks from year to year depending on emergent weather conditions.

Phenology Calendar

A simple method for tracking the seasonal development of pests is a phenology calendar. Phenology is the study of relationships between periodic biological events and seasonal climate changes. Annual natural events such as pest behavior and plant development are often better correlated with seasonal, climate changes than specific calendar dates.

Growing Degree-Day Tracking

This method, referred to as growing degree day (GDD) tracking, involves measuring daily temperatures. For insects, mites, and plants, development is triggered when daily average temperatures rise above a certain base temperature.

Unmanned Aerial Vehicles for Pest Monitoring

Unmanned Aerial Vehicles (UAVs) also known as drones are defined as powered aerial vehicles that can fly autonomously or be piloted remotely (See Figure 20.4). Many people refer to UAVs as Unmanned Aerial Systems (UAS), which reflects the complexity of systems onboard these vehicles. UAS include stability and navigation systems, communication and control systems and, if needed, data collection and analysis systems. UAS have either fixed or rotary wings.

Geo-Referencing and Image Processing

Cameras are the most common sensors to capture plant reflectance for precision agriculture. These payloads can be mounted in a UAS to capture the visual signatures of plant leaves, canopy temperatures and plant reflectance at different spectrums.

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