Sweet corn sweet corn sweet corn..Corn Earworm (Helicoverpa zea)

The corn earworm is the most serious sweet corn pest because it feeds directly on the marketable product. Once

earworms have become established within the ear, control is impossible, so a preventive program in necessary.

Earworms are variable in color, but they have a brown head without markings and numerous microscopic spines covering their body. Earworms spend a relatively short period of their life feeding in a site that can receive an adequate insecticide application. A preventive program, especially on late season corn, is necessary to ensure that damaged ears are at a minimum.

Corn earworms overwinter as pupae in underground cells. Some adults from these pupae begin to emerge as early as late March, others may not appear until August. There are generally four generations each year, however, overlap is great and adult moths that can lay eggs may be present in significant numbers throughout most of the growing season.

Female moths search out green silks on which to lay single eggs. Following hatch, the small larvae often eat the egg shell before beginning to feed on the silk. Corn earworms generally complete their development in 14 to 16

days. Full grown worms leave the ear and pupate in the soil. The new adult will be active in another 10 to 14 days.

A preventive program against corn earworms may begin when 10% of the ears are silked. Repeated sprays at three to five day intervals until 90% of the silks have wilted should give a high percentage of earworm-free ears during early and midseason. Control is more difficult late in the Season. Late in the season, even shortening of spray intervals may produce only 90% or fewer clean ears. Sprays should be driven deep into the silks. Corn hybrids having a long, tight-fitting shucks suffer less damage than those with shorter or looser shuck leaves.

Controls

Biological: The hemipterans, Orius, Nabis, Gencoris, and the lacewing, Chrysopa, are predators. Common wasp parasites include Brachymeria ovata, Microplitis croceipes and Trichogramma spp. The tachnids, Archytas

marmoratus and Winthemia quadripustulata are effective parasites. The fungus, Nomuraea rileyi, and the microsporidan, Nosema heliothidis, are also damaging to the earworms. Bt sweet corn hybrids (Attribute™) provide more than 95 % control of corn earworm damage to the ears.

However, it is necessary to continue to monitor Bt sweet corn for corn earworm activity and use supplemental insecticide sprays when necessary.

Cultural: The time of planting will have a marked effect on injury by this insect, but will not always be the same in different years; i.e., occasionally early-planted corn will be injured, but in most years the later plantings of

sweet corn are at greatest risk to corn earworm injury. The moths prefer to lay their eggs on fresh corn silks, so corn which silks before or after the greatest abundance of moths will largely escape infestation. Generally, sweet corn which silks after most of the field corn has begun to dry down will be exposed to the greatest corn earworm egg laying. Planting of resistant varieties of sweet corn will greatly reduce earworm damage. Corn hybrids that have tight husk leaves and that provide complete coverage of the ear have reduced ear damage by corn earworm.

Monitoring: Egg laying occurs only while silks are still green, but sprays need to be repeated at 2 to 7 days intervals while silks are fresh. Once silks dry, no additional corn earworm sprays are necessary. Time of planting,

intensity of moth flight and temperature will affect spray intervals. Pheromone traps are available for monitoring this pest to determine the need for insecticide sprays and their intervals.

Application Alternatives:

Ambush 2 E (permethrin)- Apply as a foliar treatment at 6.4 to 12.8 fl oz per acre to a limit of 76.8 fl oz per acre per season.

Asana XL (esfanvalerate)- Apply as a foliar treatment at 5.8 to 9.6 fl oz per acre to a limit of 96 fl oz per acreper season.

Baythroid 2 (cyfluthrin)- Apply as a foliar treatment at 1.6 to 2.8 fl oz per acre to a limit of 10 applications per season.

Capture 2E (bifenthrin) - Apply as a foliar treatment at 2.1 to 6.4 fl oz per acre to a limit of 12.8 fl oz per acre per season. The long Restricted Entry Interval limits the use of this product to machine harvested field for

processing. Only a small fraction of the acreage in Kentucky is harvested by machine.

Diazinon AG 500 (diazinon)- Apply as a foliar treatment at 1 to 1-1/4 pt per acre.

Lannate 90 SP(methomyl)- Apply as a foliar treatment at 1/4 to ½ lb per acre per season to a limit of 8 lb per acre per season.

Pounce 3.2 EC (permethrin)- Apply as a foliar treatment at 4 to 8 fl oz per acre to a limit of 48 fl oz per acre per season.

Sevin 80 WSP (carbaryl)- Apply as a foliar treatment at 1-1/4 to 2-½ lb per acre to a limit of 8 applications per acre per season. Allow at least 7 days between sprays.

Warrior 1EC (lambda-cyhalothrin)- Apply as a foliar treatment at 2.56 to 3.84 fl oz per acre to a limit of 3.84 pts per acre.

Sweet corn sweet corn sweet corn..Corn Flea Beetle (Chaetocnema pulicaria)

Flea beetle numbers can be very high in Kentucky in the early spring following years with mild winter temperatures. Flea beetles are small, black, hard-bodied insects that hop or fly quickly when disturbed. They overwinter as adults and become active early in the spring. Flea beetles attack young corn plants as soon as the first true leaf appears. Flea beetles produce small feeding streaks or scarring on the leaves. During wet, cold periods in the spring when corn is growing slowly, damage from this pest can be severe. Only rarely will this actually kill plants. The real concern from flea beetles is Bacterial Wilt (Stewart’s Wilt), a bacterial disease of corn. The pathogen is carried inside the flea beetle. Young plants become infected as the beetles feed. Damage from Stewart's wilt is far more severe than leaf injury caused by the beetles. Wilt resistant sweet corn varieties should be selected to prevent losses. Foliar sprays should be applied if flea beetle damage appears serious.
Chemical control of the beetle should not be the only protection program for Stewart's wilt.

Controls
Cultural: In years following mild winters, producers should select sweet corn hybrids with a high level of resistance or tolerance to Bacterial Wilt (Stewart’s Wilt).
Monitoring: Check corn from emergence until 12 inches tall. Flea beetle stress may be great on late planted corn. However, early planted fields may also show noticeable damage. Treatments may be warranted it there are scattered scratch marks on approximately 50% of plants, especially if field has a history of Stewart's wilt.
Application Alternatives :

Ambush 2 E (permethrin)- Apply as a foliar treatment at 6.4 to 12.8 fl oz per acre to a limit of 76.8 fl oz per acre per season.
Asana XL (esfenvalerate)- Apply as a foliar treatment at 5.8 to 9.6 fl oz per acre to a limit of 96 fl oz per acre per season.
Diazinon 50 W (diazinon)- Apply as a foliar treatment at 1 lb per acre.
Pounce 3.2 EC (permethrin)- Apply as a foliar treatment at 4 to 8 fl oz per acre to a limit of 48 fl oz per acre per season.
Sevin 80 WSP (carbaryl)- Apply as a foliar treatment at 1-1/4 to 2-½ lb per acre to a limit of 8 applications per acre per season. Allow at least 7 days between sprays.
Warrior 1 E (lambda-cyhalothrin)- Apply as a foliar treatment at 2.56 to 3.84 fl oz per are per season to a limit of 3.84 pt per acre per season.

Sweet corn sweet corn sweet corn..INSECT CONTROL

Consumer demand for damage-free sweet corn means that growers must develop the an economical and effective management program for insect pests, especially those that attack the ear. Additional insecticide information is available from ID-36, "Commercial Vegetable Crop Recommendations."

Cutworms (Agrotis spp.)

While they are potentially very destructive, cutworms are unpredictable, and the chances of significant damage in any given year are relatively low. Sweet corn can be seriously damaged by cutworms from planting through mid-June while the plants are less than 18 inches tall. Serious losses are often associated with wet springs that have caused a delay in planting.
Cutworms are the larvae of moths. These night-flying moths are frequently attracted to lights at night. The 1-1/2 to 2-inch moths are dull-gray to brown with yellow, gray, light brown, and black designs on the front wings. The hind wings are usually solid in color and lighter than the front wings. Moths lay eggs singly or in clusters on the leaves of grasses, weeds, other host plants, and sometimes on the bare ground. Cutworms are smooth-skinned and somewhat shiny. They range in color from gray to dark brown with distinctive stripes and spots. When fully grown, cutworms can reach 1-3/4 inches in length. Cutworms commonly coil up in a "c" shape when disturbed.
Cutworms feed mostly at night and hide during the day under clods of soil or in burrows below the soil surface. They cut off the stalks of young plants at or just below the soil surface and feed on the buds or leaves. They rarely consume the entire plant, but more commonly move to the next plant in the row or to another row. Infestations typically are not uniform within a field, so the loss of a plant stand tends to occur only in parts of a field.
Controls
Biological: Cutworms are parasitized by tachinids, Archytas, Bonnetia, Eucelatoria and Winthemia spp., by braconids, Apanteles, Chelonus, Meteorus, and Microplus spp., and by inchneumonids, Campoletis, Hyposter, Nepiera and Pterocornus spp. They are also readily fed on by many species of birds.
Cultural: Eliminate weeds from field margins and prepare fields at least two weeks prior to planting to destroy cutworm food sources and egg laying sites. Monitoring: Early detection of economic infestations means that an insecticide can be applied before serious damage occurs. Careful scouting of corn fields is the most effective means of detecting economic infestations of
cutworms. Scouting for cutworms should begin as soon as the corn emerges and continue twice weekly until the plants reach 18 inches high.
In at least five areas of the field, examine 20 consecutive plants. Note the number of plants that are cut, wilted, or showing signs of leaf feeding. While walking through the field, observe the evenness of cutworm infestations.Look for live cutworms around freshly damaged plants. First, check under clods around the base of plants. Then, dig up an area three inches in radius and three inches deep around the plant. Under dry conditions, cutworms are found lower in the soil.
When 3% or more of the plants are cut and two or more small cutworms (1" or smaller) per 100 plants are observed, then control action may be warranted. Exceptionally high or low stand counts can be used to adjust the 3% value. If conditions are borderline, scout the field again in 24 to 48 hours or until a final decision is made.

Application Alternatives :

Ambush 2 E (permethrin)- Apply as a foliar treatment at 6.4 to 12.8 fl oz per acre to a limit of 76.7 fl oz per acre per season.
Baythroid 2 (cyfluthrin)- Apply as a foliar treatment at 0.8 to 1.6 fl oz per acre to a limit of 10 applications per season.
Force 3 G (tefluthrin) soil applied T-band or infurrow at 4 to 5 ounces per 1000 row feet.
Lorsban 4 E (chlorpyrifos)- Incorporate preplant at 2 to 4 pt per acre or apply as a foliar treatment at a rate of 2 to 3 pt per acre.
Lorsban 15 G (chlorpyrifos)- Incorporate preplant at 6.75 to 13.7 lb per acre or use a banded or T-band application at a rate of 8 oz per 1000 row feet.
Pounce 3.2 EC (permethrin)- Apply as a foliar treatment at 4 to 8 fl oz per acre to a limit of 48 oz per acre per season.
Warrior 1 EC (lambda-cyhalothrin)- Apply as a foliar treatment at 2.56 to 3.84 fl oz per acre to a limit of 3.84 pt per acre per season.

Sweet corn sweet corn sweet corn..Special concerns

1. Separation (isolation): To avoid cross-fertilization, a separation distance of 700 feet is recommended when planting white, yellow or high sugar varieties. If such a distance is impractical, a distance of 250, while giving some contamination, will not materially affect quality. Isolation can also be maintained if there is a minimum of 14 days difference in the maturities of different types. Super sweet types (with sh2 gene) must be isolated from all other corn types or the kernels will be starchy and not sweet. It is best to isolate se types as well.

2. Obstacles to growth: The high sugar types of sweet corn are more difficult to grow than standard corn. High sugar corn is generally more attractive to insects, birds, groundhogs and raccoons and is more susceptible to heat and drought stress than standard sweet corn. Irrigation is essential to ensure high quality in the high sugar types.

3. Tips: Sweet corn will do well in all areas of Kentucky, but well-drained soils are essential for good results. A good seedbed is essential for successful seed germination and resulting good stands. Fescue sod is ideal prior to sweet corn production. Plowing should be done several weeks in advance of planting to allow the ground to settle and the grass to decompose. Disking the soil 3 to 4 times before planting will help in preparing a good seedbed.

Sweet corn sweet corn sweet corn..cultur practices

 Cultur practice

For best results, sweet corn seed should be planted after the soil temperature has reached 60*F. In most parts of High sugar type corn, while lacking the creamy texture and flavor of the standard and sugary enhanced corn, is commercially attractive due to it higher sugar level and the fact that conversion of sugars to starch is slower than other corn types or is incomplete. Thus, super sweet corn will remain sweeter much longer than other corn type sand its crisp kernels hold up much better when mechanically harvested.

The high sugar types of sweet corn are more difficult to grow than standard corn. Seed germination percentages of super sweet types may be reduced, particularly under cold soil conditions. Weather in Kentucky can be unpredictable, so at present, use of standard varieties for very early plantings intended for early markets is encouraged. High sugar corn is also generally more attractive to insects, birds, groundhogs and raccoons and is more susceptible to heat and drought stress than standard sweet corn. Irrigation is essential to ensure high quality in the high sugar corn types. Soil analysis tests are recommended to determine needs for phosphorus, potassium and/or nitrogen amendments.Effective pest control is particularly important because the product ends up on the tables of the public

CORN.....APPLICATION FERTILIZER & PLANTING ??

Fresh, homegrown corn can be a tasty summer treat, but growing it can take a lot of time and gardening resources. Corn plants rely heavily on nitrogen to grow, and several applications of fertilizer, not just at planting but also during the growing season, may be necessary. The timing of these fertilizer applications is also critical to the growth and health of the corn plant.

        Before Planting

o    Fall application of rotted compost enriches the soil. Application of 12-12-12 fertilizer before spring planting ensures soil rich enough to support corn growth. Broadcast 3 to 4 lb. fertilizer and band through the soil every 100 square feet. A broadcast spreader scatters up to two-thirds of the fertilizer over the garden soil. It is then tilled 3 to 4 inches down. Banding spreads the remaining fertilizer to the sides and slightly under each furrow.

Side-Dressing

o    Corn has a fairly long growing cycle, from spring through late summer. Therefore, corn plants will need side-dressings of nitrogen-rich fertilizer throughout their growing cycle. Side-dress the corn plants when they are 10 to 12 inches tall by applying 1 lb. ammonium nitrate (30-0-0) per 100 ft. row, keeping the fertilizer about 6 inches away from the plant base. Reapply the fertilizer about one week after the first tassels show.

Fertilization Considerations

o    Sandy soils and a rainy season will impact how often corn plants need to be fertilized. Sandy soil has fewer nitrogen resources than other types of soils. Heavy rains will often wash away the fertilizer before it has a chance to mix in the soil and be absorbed by the corn plants. While some corn plants may survive these conditions without additional fertilizer side-dressings, the plants may succumb more easily to pests and diseases.

Nutrient Deficiencies

o    Corn plants will show signs of nutrient deficiencies if they have not received and absorbed enough fertilizer due to poor soil conditions. A corn plant deficient in nitrogen will have soft, pale green leaves that bend easily and do not protect the plant well. Corn plants deficient in phosphorous will tend to have leaves that are purplish in color. Deficiencies can be rectified with side-dressings of the requisite fertilizer.

AWASSS! Antherigona sp.(lalat bibit) musim hujan serang kebon jagung

A.Pendahuluan
Hama lalat bibit (Antherigona sp) merupakan salah satu hama yang merugikan pada  tanaman jagung. Hama lalat bibit menyerang tanaman jagung yang masih muda terutama yang ditanam pada musim hujan.

Lalat bibit (Atherigona exigua)
Menyerang tanaman muda, akibat serangannya seringkali mematikan tanaman. Lalat bibit digolongkan ke dalam :
Ordo : Diptera.
Famili : Antomyiidae.
Genus : Atherigona.
Spesies : Exigua.

Mengingat kerugian yang ditimbulkan cukup besar, diperlukan tindakan pengendalian secara terpadu untuk menekan tingkat serangan sampai batas yang tidak merugikan. Pengendalian hama terpadu merupakan komponen pengendalian yang tepat karena lebih mengutamakan pengendalian secara alami seperti pemanfaatan parasit, predator dan pathogen hama.

B.Gejala dan Penyebarannya
Gejala diikuti daun yang masih muda menggulung layu karena pangkalnya tergerek larva. Larva yang sampai ke titik tumbuh menyebabkna tanaman tidak dapat tumbuh lagi. Penyebabnya adalah lalat bibit (Antherigona sp), dimana imago aktif pada siang hari pukul 16.00, periode imago 7 hari. Telur diletakkan pada permukaan bawah daun secara terpisah satu sama lain. Periode telur 1-3 hari, lama stadium larva antara 8-10 hari dan stadium pupa antara 5-11 hari dan stadium imago rata-rata 8 hari. Pupa berada dalam tanah dekat tanaman, namun kadang-kadang dalam tanaman.

C.Pengendalian
Pengendalian hama terpadu merupakan pengembangan teknologi pengendalian lebih dilakukan pada pengendalian yang bersifat alami dan sekecil mungkin mengurangi penggunaan insektisida. Beberapa cara pengendalian lalat bibit adalah sebagai berikut:
1.Pengendalian Hayati.
Pengendalian hayati dapat dilakukan dengan menggunakan parasitoid dan predator. Parasitoid untuk lalat bibit adalah Trichogramma sp dan parasitoid untuk larva adalah Opius sp dan Tetrastichus sp. Predator imago adalah clubiona japonicola.

2.Pergiliran tanaman
Menanaman jagung secara berturut-turut harus dihindari, karena akan member peluang pada lalat bibit untuk tumbuh dan berkembang. Pergiliran tanaman  sebagai upaya untuk memutuskan daur hidup lalat bibit karena tidak ada persediaan makanan.

3.Penggunaan Insektisida
Penggunaan insektisida harus dengan bijaksana, terbatas dan selektif baik jenis maupun cara aplikasinya. Insektisida yang digunakan korbufuran 10 g/kg benih melalui titik tumbuh dan untuk daerah endemic menggunakan Tiodicarb 75WP 15 g/kg benih atau karbosulfan 2,5 g/kg benih.

4.Menanam Varietas Unggul Baru yang tahan HPT
Menanam beberapa varietas yang tahan terhadap serangan lalat bibit seperti yang telah ada di pasaran.Baik pada jagung maupun jagung manis.

Pengawasan yang terlambat akan berakibat fatal pada hasil yang akan di peroleh. Hal ini karena jika tanaman yang terserang berakibat titik tumbuh tanaman tidak muncul, sehingga bunga tidak terbentuk akibatnya tanaman akan terbentuk anakan atau pertumbuhan tongkol yang tidak sempurna sebagai akibat pembuhaan yang tidak sempurna.