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Corn - DOC


									                            CORN (FIELD & SWEET)
1. Varieties
            Field Corn:        Pioneer Hybrids, Local selections
            Sweet Corn:        Renat Hybrid, Sugarburst
            Seed rate:         5 - 10 lbs per acre (depending on seed size)
2. Seed Treatment
Commercially available seed is usually pre-treated to protect against insects and fungi. Locally
produced seed can be treated with a malathion + captan dust.
3. Spacing and Planting
Seeds may be planted mechanically in rows 30 to 40 inches apart with seeds 6 to 9 inches apart
in the row. Mechanical planting can be done using a Stanhay Seed Drill or a cotton/corn planter.
 Since seed size is very variable in corn varieties, the hole-size in the seed belt or seed plate has
to be selected accordingly. By hand, holes can be made 12 inches apart along the row, placing
2 seeds in each hole.
4. Seasonality
Corn may be planted throughout the year with irrigation. Under rain-fed conditions it is safe if
planted during August and September, since yield is positively influenced by soil moisture
availability at tasseling.
5. Duration of Crop
This varies with variety, but is approximately 3 months to harvest for roasting and sweet corn.
6. Weed Control
       a)      Pre-plant herbicides:
            If young annual weeds are present in the field apply 2 pints (950 ml)/acre of
            paraquat (Gramoxone Super, Millquat, Herbiquat).
            For hard to kill annual weeds e.g. whitehead bush (Parthenium sp.), wild poinsettia
            (Euphorbia spp), apply a mixture of paraquat and diquat (Reglone) at rates of 2
            pints (950 ml) per acre for both.
              For hard to kill annual and perennial weeds apply either glyphosate (Roundup,
            Wopro-glyf) or sulfosate (Touchdown) at recommended label rates.
       b)      Pre-emergence herbicides:
            Apply pendimethalin (Prowl 42.3 EC) at 3 1/3 pints (1575 ml)/acre.
            OR Metolachlor (Dual 960 EC) at 1 1/4 pints (570 ml) per acre.
            OR Alachlor (Lasso 4E) at 5 pints (2365 ml) per acre.
       c)      Post-emergence herbicides:

                                                      Crop Recommendation #18                CORN
        i)      Broadleaf weeds only. Apply either 2,4-D amine 6S at 2/3 pints (315 ml)
                per acre when most weeds have germinated. Spray after corn emerges and
                until it is 5 - 8 inches tall. May cause corn to become brittle - do not cultivate
                for about 2 weeks after application. Drop nozzles or hand-held knapsack
                sprayers may be used to apply 2,4-D as a directed spray, missing the leaves
                after corn is 10 inches tall, and until 2 weeks before tasseling. Avoid spray
                drift to susceptible crops. Some sweet corn varieties are sensitive to 2,4-D.
        OR Apply dicamba (Banvel 4S) at 1/4 to 1/2 pint (118-236 ml) per acre from early
        post emergence and up until corn is 24 - 36 inches tall. Not recommended for use
        on sweet corn because of crop injury.
        ii)     Young annual grasses and broadleaf weeds. Apply 2 pints (950 mls) per
                acre of paraquat (Gramoxone Super, Millquat, Herbiquat) using directed
                spray, missing the stems and leaves of plants.
7. Insect Control
                                                     ALWAYS READ THE PESTICIDE LABEL
              PEST*                PESTICIDE*         DTH*                COMMENTS*
                               Malathion OR             7
      Aphids                  Diazinon OR              7
                               Dimethoate OR           14     Perfekthion
                               Lambdacyhalothrin              Karate
                               Azadirachtin             3     Neem-X
                               Diazinon OR              7
      Cutworms                Pirimiphos-ethly               Primicid
                                                              Apply diazinon or Primicid soon after
                                                              planting; or use a synthetic pyrethroid
                                                              e.g. permethrin, cypermethrin, as
                                                              soon as damage first becomes
      Army worms              Azadirachtin OR          0     Neem-X
                               Bacillus                       Dipel, Agree, New Bt, Xentari
                               thuringiensis OR         0
                               Carbaryl OR              1     Sevin
                               Permethrin OR            1     Ambush
                               Cypermethrin OR          5     Sherpa
                               Deltamethrin OR          1     Decis
                               Lufenuron               20     Match
      Corn Earworms           Carbaryl OR              1     Sevin
                               Cypermethrin OR          5     Sherpa
                               Permethrin OR            1     Ambush
                               Deltamethrin OR          1     Decis
                               Lufenuron                      Match
                                                       20     Spray silks twice weekly for 2-3

                                                   Crop Recommendation #18                  CORN
* For application rates of pesticides - check directions for use on the pesticide label. Also
consult pesticide suppliers and/or the Extension Section of the Ministry of Agriculture.
* DTH = the minimum number of Days to Harvest from the last pesticide application. Where no
information is given please consult the pesticide supplier. Always use pesticides with short DTH
approaching or during harvest.
* The synthetic pyrethroids available are permethrin (Ambush), cypermethrin (Sherpa),
deltamethrin (Decis), and lambdacyhalothrin (Karate).
* IGR = Insect Growth Regulator. These products mainly control larvae and nymphs, but
seldom adults. Examples of IGR's available are buprofezin (Applaud), Chlorfluazuron (Jupiter),
flufenoxuron (Cascade), cyromazine (Trigard), Azadirachtin (Neem-X), and lufenuron (Match).
* Check plants carefully at least twice weekly for pests. Sucking pests are usually found on the
underside of the leaves.
* For control of a particular pest, use one of the listed pesticides per application, and rotate
with others as needed in the spray programme.
* The best times to spray are in the morning between 7.00 a.m. and 10.00 a.m. and in the late
afternoon after 5.00 p.m., when:
            a) Few insects are on-the-wing and bees are not active,
            b) The sun is not strong enough to scorch plants,
            c) Foliage is dry, and
            d) Wind speeds are low.
* The best way to spray is to wet thoroughly the stems, buds and undersides as well as the
tops of leaves.
* Always use a wetter-spreader-sticker (e.g. Citowett) at recommended rates with the spray
solution. It binds the chemical to the plant thus negating the effect of the rain, and wind.
* It's advisable to use a complete foliar fertilizer (e.g. Bayfolan, Nutrex, Novafol) in the spray
solution to help improve the quality of the water, and provide some of the nutritional needs of the
The quality of the water refers to its freedom from extraneous materials such as dirt, etc., and
also the pH (acidity or alkalinity) of the water. The pH of the water is adjusted by addition of
special adjuvants (e.g. pH Plus, Indicate 5), where necessary. Check with the Extension Staff
of the Ministry of Agriculture for more information on these areas.
* Combination of pesticides to be tank-mixed for the first time should be checked for
compatibility before use. Incompatibility negates the efficacy of pesticides in the spray
solution, and can result in plant injury - phytotoxicity.
Some information on physical compatibility can be obtained by mixing small quantities of the
pesticide materials in a separate container in the correct proportions. The combination should
be tested on a small scale to determine safety to plants before proceeding to full field-scale
Further information on compatibility can be obtained from compatibility charts, consulting with
pesticide suppliers, and the Ministry of Agriculture.

                                                     Crop Recommendation #18                CORN
* Keep spray solutions agitated to prevent settling-out of wettable powders and flowables; and
avoid leaving spray solution standing in tanks for extended periods e.g. overnight.
8. Disease Control
                                                           ALWAYS READ THE PESTICIDE LABEL
                 DISEASE*                        PESTICIDE*                      COMMENTS
                                                                        These corn diseases are of
         Corn Smut                     See comments                    sporadic occurrence and of
         (Ustilago maydis)                                              minor importance.

         Stalk Rots
         (Various fungi)

         Leaf Spots
         (Various fungi)

* DAYS TO HARVEST (DTH) = the minimum number of days to harvest from the last pesticide
application. Where no information is given, please consult the pesticide supplier.
* Check plants carefully about twice weekly for diseases. For accurate disease identification
and/or diagnosis, consult with the Extension Section of the Ministry of Agriculture.
* For application rates of pesticides - check Directions for Use on the pesticide label. Also
consult the pesticide supplier and/or the Extension Section of the Ministry of Agriculture.
9. Fertilizers
In the absence of an adequate and reliable soil testing service, the following recommendations
are given as a guide for the direct application of NPK fertilizers to the soil.
       a)      Basal dressing: during land preparation, apply in the bed and incorporate during
               rotavation the following fertilizers: -
                           3 x 50 kg bags of triple superphosphate, plus,
                           4 x 50 kg bags of 24-0-18.

Where fertilizer was not incorporated during land preparation apply 6 x 50 kg. bags of
12:12:17+2 or a similar mixed fertilizer per acre at planting.
For large-scale corn production, planting is best done using cotton/corn planters with fertilizer
drill attachments. Fertilizer drill attachments are adjusted to place the fertilizer to the side and
below the level of the seed. Specially formulated fertilizers are required, since all types do not
flow evenly in these fertilizer drill attachments.
       b)      Side Dressing: at the pre-tasseling stage (about 6 weeks after planting) side-
               dress with sulphate of ammonia at 2 x 50 Kg bags per acre.

                                                         Crop Recommendation #18               CORN
10. Harvesting
Field corn for roasting: Harvesting should take place when the grain is at the "milk" stage.
This occurs when the silks are drying and become brown, and the grain can be crushed with
finger pressure.
Field corn for milling: This should be delayed as long as practicable to allow for natural drying
of the grain in the field. In unfavourable weather or where birds or other pests cause severe field
damage to ripening corn, the crop may be harvested earlier, and dried artificially to 10 to 12%
moisture content.
Sweet Corn: May be harvested as "baby corn" where the entire cob is utilized, or later at the
"milk" stage.
11. Yields
Field corn for milling: Approximately 3 500 lbs per acre of dried grain from the hybrid varieties
and 2 000 lbs per acre from local selections.
Field corn for roasting, and Sweet Corn: Approximately 8 000 lbs per acre rain-fed and
18 000 – 20 000 lbs per acre with drip irrigation.

 DISCLAIMER: The information given herein is for educational purposes only. Reference to commercial
 products or trade names is made with the understanding that no discrimination is intended and no
 endorsement by the Ministry of Agriculture and Rural Development. Use pesticides safely. Read and
 follow label directions.

                                            Coordinating Editor : Henderson A. Williams
 Typists: Juel Hackett and M. Rose Bourne Graphics : Trevor Pollard Computer Editors : Samuel Inniss and Mark Byer

                                                                          Crop Recommendation #18                    CORN

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