CCA Pest Diagnostics and Disease Management

Question 1

Which pathogen causes common corn smut, characterized by large galls on ears and tassels?

Accepted Answer

Ustilago maydis

Answer

Puccinia sorghi

Answer

Exserohilum turcicum

Answer

Fusarium graminearum

Question 2

Soybean sudden death syndrome (SDS) is caused by which pathogen?

Accepted Answer

Fusarium virguliforme

Answer

Phytophthora sojae

Answer

Sclerotinia sclerotiorum

Answer

Diaporthe sojae

Question 3

Wheat streak mosaic virus is primarily transmitted by which vector?

Accepted Answer

Wheat curl mites

Answer

Aphids

Answer

Leafhoppers

Answer

Thrips

Question 4

Northern corn leaf blight (NCLB) lesions are best described as:

Accepted Answer

Large cigar-shaped grayish-green lesions parallel to leaf veins

Answer

Small, circular tan spots with dark borders

Answer

Yellow halos surrounding brown necrotic centers

Answer

Purple streaks running lengthwise on leaves

Question 5

Frogeye leaf spot in soybeans is caused by which pathogen?

Accepted Answer

Cercospora sojina

Answer

Phakopsora pachyrhizi

Answer

Septoria glycines

Answer

Colletotrichum truncatum

Question 6

Which symptom pattern is most characteristic of bacterial leaf blight in soybeans caused by Pseudomonas savastanoi?

Accepted Answer

Water-soaked angular lesions that turn brown with yellow halos

Answer

White powdery coating on upper leaf surface

Answer

Circular lesions with tan centers and purple borders

Answer

Dark, sunken lesions on pods and stems