BYDV Assist is a scouting app developed to assist in spray timing for controlling Barley yellow dwarf virus (BYDV), primarily transmitted by aphids. The app aids in inspecting fields for aphid pressure before considering foliar insecticides to manage primary infections and prevent secondary spread. It calculates the timing for controlling secondary aphid generations crucial for effective BYDV management in autumn.

The app determines the moment when the second generation offspring reach a level causing widespread infection, based on accumulated daily average temperatures above 3°C. By using current and historical weather data, users can predict the occurrence of the 170 degree-day (DD) threshold for secondary aphid spread, with warnings provided at key stages to facilitate timely field inspections and spray recommendations.