The VT stage arrives when the last branch of the tassel is completely visible. VT begins about 2 to 3 days before silk emergence. The plant is nearly at its full height. Pollen shed begins, lasting about 1 week on an individual plant basis and 1 to 2 weeks on a field basis. The interval between VT and R1 can fluctuate considerably depending on the hybrid and the environment. Drought stress lengthens this interval.
GDUs Required** to reach VT depends on maturity and is approximately:
|Scout for these Common Pests and Diseases||Timing*|
|Corn Earworm||Arrival of adult moths from southern states varies each year. Corn at VT to R1 is most attractive to egg-laying females. Scout at R1 or when a significant moth flight is captured in pheromone traps.|
|Corn Rootworm||Larval feeding is most extensive in early through mid-July in most regions of the Corn Belt.|
|European Corn Borer||As the true stalk develops and European corn borer larvae increase in size, larvae can be found tunneling into the stalk.|
|Eyespot||V6 through R4. Disease primarily found in northern environments.|
|Goss's Wilt||VE through R6. Disease primarily found in Nebraska and portions of other western states.|
|Gray Leaf Spot||VT through R4.**|
|Japanese Beetle||VT through R1, until pollination is complete.|
|Northern Leaf Blight||VT through R4.**|
|Southern Leaf Blight||VT through R4.**|
|Western Bean Cutworm||Initiate scouting based on local pheromone trap captures of adults. If trap data are unavailable, begin scouting at VT.|
* Information from Pioneer and Iowa State University Extension.
*** Scout for these diseases earlier in seed production fields.
Use this information as a guide and it should not be the only factor in making decisions.