By Nicolle Ritchie and Eric Anderson
Whether from pests, diseases, weather-related stress, herbicide injury or nutrient deficiency, early-season crop damage can result in all sorts of challenges that may ultimately reduce farm profitability. Determining the root cause and severity of the problem is an important diagnostic step on the path to addressing the problem.
Damage caused by vertebrate pests such as deer, Canada geese and voles can start early in the season and often result in significant stand loss. Invertebrate pests such as black cutworm, seedcorn maggot or slugs are early attackers of soybeans when conditions are right. Root rot caused by Phytophthora, Pythium, Rhizoctonia and Fusarium species can affect emergence and seedling survival, often in wet soils. Herbicides and high-salt fertilizers may burn vulnerable stems or cotyledons. Nutrient deficiency symptoms may be more easily found on soybean leaves as uptake is inhibited by cool weather and underdeveloped root systems.
When you come across a symptom or sign that soybean stress or damage is occurring, consider the following steps to troubleshoot the root cause.
Step 1. Identify the initial symptoms. What caught your eye and caused you to investigate further? This may be leaf discoloration, feeding damage on leaves, a lack of emergence, etc.
Source : msu.edu