Login

Pests and Disease

Pest Models

Models of pest development use temperature data to determine the risk of pest infestation and spread. The data that is required for these models is collected and displayed on the SensorSentry platform. The intuitive presentation of the data facilitates easier dissemination and more timely interpretation of information to optimize pest management strategies.

The development of many organisms that cannot internally regulate their own temperature is dependent upon the environmental temperatures they experience. Insects require a certain amount of thermal energy (heat) to develop from one stage in their life-cycle to another e.g. eggs to adults. Due to seasonal fluctuations in temperature, the use of calendar dates is an unreliable source in determining insect development. Measuring the amount of heat accumulated over time provides a physiological time scale that is biologically more accurate than calendar days. This procedure is known as a phenology model. Phenology models predict the series of events in an insect's development. This information can then be utilized along with crop scouting to ensure that insect infestation is minimized and crop health maximized.

Phenology models use growing degree days (GDD's) to determine the development of the insect. Two parameters are used when referring to the effect of temperature on an insect's growth and development. The lower threshold is the temperature where insect development stops. The upper threshold is the temperature at which the rate of growth or development of the insect begins to decrease. Both lower and upper thresholds are determined through carefully controlled research and are unique for a specific insect.

Each stage of an insect's development has its own total heat requirement. Development can therefore be estimated by accumulating GDD's between upper and lower temperature thresholds throughout the season. The accumulation of GDD's from a starting point can help predict when a developmental stage of the insect will be reached. Phenology models do not indicate whether control action is warranted, but rather when a pest will reach susceptible or critical life stages. Crop scouting and traps will confirm whether action is required.

Pest models are comprehensively validated after development to ensure that they provide the most accurate warnings on critical pest phenological growth stages. The information generated from these models can then be used to determine whether control action is required. Many of the new environmentally benign, selective insecticides have specific modes of action that are best targeted at a particular life stage of the insect. Phenology models advise when these critical life stages have been reached. This enables the insecticide to be applied at the correct time to maximize its efficiency and gain the best possible control of the pest. The SensorSentry data platform can be invaluable when structuring successful pest management strategies.