Agronomy Degree Practice Exam

What can be detected on a crop when exposed to a black light?

1. Leaf blight

2. Aflatoxin

3. Cyst nematodes

4. All of these

The correct answer is: Aflatoxin

When exposed to a black light, the presence of aflatoxin can be detected on crops. Aflatoxins are toxic compounds produced by certain molds, notably Aspergillus species, which can infest crops such as corn, peanuts, and tree nuts. Under ultraviolet light, aflatoxins exhibit fluorescence, allowing for their identification and quantification on infected crops. This property is particularly useful in agricultural practices and food safety monitoring, as aflatoxins pose significant risks to both human and animal health. Detecting aflatoxin is crucial for preventing contamination in food supplies, ensuring that products meet safety standards before they reach consumers. While conditions related to leaf blight and the presence of cyst nematodes can adversely impact crops, they do not exhibit fluorescence under black light, making them undetectable by this method. Thus, only aflatoxin is specifically identifiable using black light, highlighting its importance in agronomy and food safety.