Group Title: Agronomy Notes
Title: Agronomy notes
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 Material Information
Title: Agronomy notes
Uniform Title: Agronomy notes (Gainesville, Fl.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Agronomy Department
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Place of Publication: Gainesville
Publication Date: August 2010
Copyright Date: 2010
Subject: Crops and soils -- Florida   ( lcsh )
Crop yields -- Florida   ( lcsh )
Agriculture -- Florida   ( lcsh )
Agronomy -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
Statement of Responsibility: Florida Cooperative Extension Service, University of Florida, Institute of Food and Agricultural Sciences.
Additional Physical Form: Also available to subscribers via the World Wide Web.
Additional Physical Form: Electronic reproduction of copy from George A. Smathers Libraries, University of Florida also available.
General Note: Description based on: January 1971; title from caption.
 Record Information
Bibliographic ID: UF00066352
Volume ID: VID00126
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000956365
notis - AER9014


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IFAS Extension


Growth Stages of Corn ....................................... Page 2
Fungicide Use in Corn ....................................... Page 2


Cutting Losses in Hay Storage........................ Page 4


Volunteer Canola ......................... Page 3


Calendar ...................... .............. ......... Page 5

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Employment Opportunity-Affirmative Action Employer authorized to provide
research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Office. Florida Cooperative
Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Millie Ferrer-Chancy, Interim Dean.

"Agronomy Notes" is prepared by: Maria Gallo, Interim Chair and Y. Newman, Extension Forage Specialist ... !II. I 1. 1. J. Ferrell, Extension
Weed Specialist I i.. I11. ni. 1,i.. .J. Marois, Plant Pathologist i,, '- i -!i. I ... D. Wright, Extension Agronomist ni ia id I. .1., The use of trade
names does not constitute a guarantee or warrant of products named and does not signify approval to the exclusion of similar products.


Dr. David Wright, Extension Agronomist

Noth Florda REC, Quing

Growth Stages of Corn

Corn growth stages are shown below. Management decisions can be made during different growth stages that impact yield.
Consumers know corn best from the R3 stage which is commonly referred to as the roasting ear stage which is about 18-22 days after
silking. The growth stages are signified by vegetative stages which occur prior to silking and the reproductive stages which have to
do with ear development. Each leaf stage is defined according to the uppermost leaf whose leaf collar is visible. The first part of the
collar that is visible is the back which appears as a discolored line between the leaf blade and leaf sheath. The oval-shaped first leaf is
a reference point for counting upward to the top visible leaf collar. However, at V6 the V1 leaves may fall off due to expansion of the
stalk and the first leaves can only be identified by splitting the stalk and identifying the interode expansion at the base of the plant.

Vegetative Stages

VE emergence
V1 first leaf
V2 second leaf
V3 third leaf
V6 sixth leaf
V9 ninth leaf
V12 -twelfth leaf
V15 fifteenth leaf
V18 eighteenth leaf

Reproductive Stages

R1 silking
R2 blister
R3 milk
R4 dough
R5 dent
R6 physiological maturity


Dr. David Wright, Extension Agronomist

Noth Florda REC, Quing

Dr. Jim Marois, Plant Pathologist


Fungicide Use in Corn

There has been a lot of discussion about the use of fungicides on corn the past several years. Diseases can be devastating
on any crop if proper rotation and planting date are not followed. Corn is susceptible to rust, both common and southern,
and leaf blight. Corn that is planted later than normal is more susceptible than early planted corn and corn planted after
corn in the same season is highly susceptible to large yield losses from diseases. On a survey done for grain yield loss in
Iowa, mean yield response to fungicides was greatest when disease severity in a field at R5 (dent at 35-42 days after
silking) was high. If disease severity on the ear leaf at R5 was <5 percent, mean yield response to fungicides was 4.83 bu/
A, however, when disease severity on the ear leaf at R5 was >5 percent, the mean yield response was 9.46 bu/A. Based on
the price of corn of $3.72 and $24 product + application, the breakeven yield response is 6.45 bu/A". In Florida we have
seen disease on corn to be at higher levels than these. Therefore, growers should consider monitoring disease levels in
their corn crop and if fungicides are applied leave some areas in the field untreated to determine the economics of
treatment for future years. The southeast may have higher diseases on corn due to a longer growing season and more
favorable environmental conditions (rain).

Weed Control

Volunteer Canola

Twice this season I have received calls about "some strange
mustard looking plant" that was growing in a production
field. Both instances of this weed was following a rye cover
crop. The greatest concern was that this weed was
seemingly not affected by multiple applications of
glyphosate. So what is this weed?
We are not exactly sure about this weed because getting a
positive ID on anything in the mustard family is very
difficult, but I suspect that this is canola. In some areas
where rye seed is produced, they have also historically
grown canola. In recent years, much of the canola grown is
Roundup Ready. Since this plant seems to be surviving the
glyphosate applications with no apparent injury, I have
surmised that Roundup Ready Canola seed was transported
here in rye seed. It is important to keep a watch for this
weed. It is relatively easy to see since it can look almost
blue in color. If you see this weed, you should act quickly to
get it removed before going to seed. Volunteer canola can
be somewhat difficult to control, but next is a list of
commonly used herbicides and their relative efficacy against
this weed.

Canola Plant. Photo: Dan Muillins, Santa Rosa County

Peanuts Relative efficacy
Valor (PRE) Good

Cobra Fair

Basagran Fair

Cadre Excellent

Sencor (PRE) Good/excellent

Cobra Fair

Basagran Fair

Pursuit or Extreme Excellent

Raptor Excellent


Callisto Excellent

Accent Excellent

Atrazine Fair/good

2,4-D Fair

Dicamba Good

Steadfast Excellent

Small Grains

Express Excellent

Harmony GT Poor

Harmony Extra Excellent

2,4-D Fair

Dicamba Good


Ignite Fair

Diuron Good/excellent

Envoke Excellent??

Dr. Jason Ferrell, Extension Weed Specialist

Forage Dr. Yoana Newman, Extension Forage Specialist

Cutting Losses in Hay Storage

This year has been an excellent one for .. v *

Several factors have contributed to A "'
make this possible-the cool-spring
temperatures, good distribution of rain
and a few bouts of the necessary dry
weather. Many ranches are well
stocked with hay and we still have
August and September to go. As
challenging as hay production is in our
state, this excellent source of nutrition
needs to be further protected after
bales are made to warrant indefinite
storage (if storing inside) or to extend
outside storage with minimum nutrient aro
losses from exposure to weather.

If storing hay outside, the site selection s i a
is an important consideration. A great
extent of the spoilage of round bales Practical covered structure with- for hay storing
occurs from moisture that is absorbed Photo: Y. Newman
from the ground, which can be as much
or more than the infiltration from the top. The spot selected should be a well-drained, open, sunny location avoiding
areas under trees. It is recommended to select a site close to the feeding area because bales become harder to handle as
they weather. As much as possible, avoid hay-to-soil contact; this isolation can be achieved by storing on concrete pad,
crushed rock, or any other material that would keep the bale dry and from touching the soil directly. An important
consideration for Florida is to keep away from storing near wire fences or other objects that may attract lightning. If
large number of rolls have been produced, it is advisable to split the storage at several locations to minimize potential
loss to fire. When storing, ideally, leave a clearance of 3 feet between bales to allow drying after rain events. Bales can
also be stored end-to-end with flat ends of bales butted tightly and avoid having the rounded sides touching. Touching
of bales will increase moisture accumulation. Orientation of the row of bales is also important; the north-south
orientation of the bale row provides maximum sun exposure compared to the east-west orientation, which contributes
to keeping the bales dry.

Barn storage is an effective method of storing hay; under this modality, hay losses are typically around 5% compared to
310.', or more when storing outside. An added benefit of storing hay in a barn is the protection from sun and
preservation of hay color. However, if storing inside or outside using covers (tarp, plastic sheeting, or other fabric), the
target is to keep moisture from building up. High moisture levels (over 20' i.) will promote mold growth that significantly
decrease hay quality and increases heating of the bales and with it the fire risk.

There are many options for protecting your hay, and it varies from the resources available at each location. The extra
effort to protect your hay will pay dividends.


To follow the link, press "Ctrl" and put cursor over link, and "click."


Ntiona1 Goat Confere "

"Strengthening the Goat Industry" i
September 12-15', 2010 '
http:llwww.famu.edulgoats .

*, ,- ,
Oo oooe

Aug. 1-5 Ecosystem Restoration Conference (NCER), Baltimore, MD

Sept. 12-15 National Goat Conference, Leon Civic Center, Tallahassee

Sept. 14-17 International Citrus & Beverage Conference, Clearwater Beach

Sept. 20 Florida Equine Institute and Allied Trade Show, Southeastern
Livestock Pavillion, Ocala

Oct. 11-14 UF-CTA Potential Invasive Pests Workshop
Coconut Grove (Miami), Mayfair Hotel

Oct. 19-21 Sunbelt Ag-Expo http:/ /
Moultrie, Georgia

Oct. 31-Nov 3 American Society of Agronomy Annual Meeting Long Beach, California

Nov. 16-18 Tomato Disease Workshop, Balm (Gulf Coast REC)

Sponroreld by: UF IFAS. Certer for Tropicl A gri-culture (CT-r) I USDA TSTr^R I A^PHIS PPC


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