Climatic conditions, soil and water requirement:

Altitude

Maize can be grown at altitudes between 0-2200 m.a.s.l. Growing zones are differentiated as Highlands, Midlands and Lowlands. This influences the choice of the appropriate variety.

Soil type and conditions

Maize requires deep, well drained, fertile alluvial or loam soils with good water holding capacity and high organic matter content.  The ideal pH should be 5.5-7.5.

Temperature range

Maize has a wide range of tolerance to temperature conditions. Optimal day temperatures should be 25-30 ^oC.

Maize is especially sensitive to moisture stress around the time of planting, tasseling and cob formation. It does best with 600-1200mm of rain during the growing season

Rainfall

Maize is especially sensitive to moisture stress around the time of planting, tasseling and cob formation. It does best with 600-1200mm of rain during the growing season.

Recommendations for land preparation

(1)Consider minimum tillage to conserve soil, water and nutrients, and to reduce cost and workload.

(2)Ploughing can be done using chisel ploughs, hand hoes, oxen or tractor drawn implements to aerate the soil but avoid excessive soil disturbance (fine tilths).

(3)In gentle to moderately sloping fields, use contour farming techniques. This requires setting out of contour lines and planting soil conservation crops (eg. Vetiver)  along the contour lines. Land preparation activities and planting is done parallel to these contour lines.

Planting materials

Common planting materials include certified seeds and farmer saved seeds. Certified seeds are produced by registered seed companies and should be bought from reputable agro-dealers.

In selecting maize seeds, a choice can be made between Hybrid varieties and Open Pollinated Varieties (OPVs). Hybrid varieties are potentially higher producing but are not suited for seed saving (propriety rights, genetic variability). Farmer saved seeds are alternatives where certified seeds are not available or considered too expensive. The selection process for seed saving should include observing growth and tolerance to adverse conditions. Select grains from the middle section of the selected (saved) cobs and avoid grains from the base and the tip of the cob, damaged or wrinkled seeds.Some recommended certified seed varieties for western Kenya region include the following: SC Duma 43, SC Sungura 301, SC Punda Milia 55, DH04, PH04, DK8031, DK8033, DK777, Pioneer 30G19, Aminika 504, Aminika 505, Tsavo 3106, Haraka 101, H513-520, H624, WS 501, WS 502, WS 505, WS 509.The website of Seed Sector Platform Kenya (www.seedsectorplatformkenya.com) gives a good overview of available seed varieties.

Plant at the onset of rains to enable the crop to take advantage of nitrogen flush.

Plant parallel to the contour lines  especially in sloping field.

Recommended Spacings:

Maize pure stand: 75cm x 25 (wet areas) or 90cmx30cm (drier areas); Place 1 or 2 seeds per planting hole, 5 cm deep in dry soil and 2.5-5 cm deep in moist soil. Seed rate is 10 kgs /acre (25 kg / hectare).

Maize and beans intercropped:

With double row beans, maize spacing is 90 x 30 cm, 2 seeds per planting hole. Beans are spaced 30 x 10-15 cm.

Reduce the negative shading effect from maize on beans by alternating planting of two or more rows of maize (at pure stand spacing) with two or more rows of beans.

Growing of maize in Kenya is generally rain fed, but irrigation can be used to bridge dry spells and will contribute to increased yields.

In areas of low rainfall, irrigation is particularly valuable at the time of tasseling & fertilization.  Irrigation methods applied must observe efficient water-use and wise application to avoid nutrient leaching and waterlogging.

Minimum tillage techniques, including sub-soiling (ripping,) will result in a higher organic matter content of the soil, which will improve the water-holding capacity. The use of mulch, especially in early growth stages, will reduce evaporation from the soil.

Manage weeds through conservation agriculture practices or through inter-row cultivation as follows:

1^st weeding 3-4 weeks after germination and 2^nd weeding at “knee-high” stage ( 6-7 weeks after planting).

Additional weeding, until the plant canopy is closed, can be beneficial.

Intercropping of maize with Desmodium will reduce the infestation with Striga by triggering suicidal germination of Striga.

Soil testing should be done before planting to guide the choice of fertilizer and application rate.

Application of conservation farming approaches such as minimum tillage, permanent soil cover, crop rotation and soil conservation measures will improve soil biology and fertility.

The general crop nutrient recommendation for maize is as follows:

At planting: Apply 50 kg/acre of NPK blend. The fertilizer (one bottle cap) is placed in the planting hole and mixed with the soil before placing the seed.

To ensure better results, apply two handfuls of well-decomposed manure/compost in the planting hole then add NPK blend at half the rate (25 kg/acre) before placing the seed.

At top dressing: A single application of 50 kg/acre of a CAN fertilizer is applied when the maize crop is about 30 cm high. The fertilizer is placed in a ring around the maize stem (5 cm away from the stem).

Practice conservation farming approaches like minimum soil disturbance, permanent soil cover, and crop rotation to improve soil structure and soil biology.

Implement soil conservation measures to reduce soil erosion and improve water holding capacity of the soil

Apply IPM principles for increased use of biophysical methods of pest control and reduced use of agrochemical methods.
Apply push pull technology to trigger suicidal germination of Striga, and to reduce the incidence of Fall Army Worm in the maize crop.

To reduce Pest infestation, apply the following IPM strategies:
• Crop rotation and field sanitation.

• Intercropping and early planting.

• Push-pull methods and natural enemies.

• Rogueing affected plants.

(i)Fall Armyworm (Spodoptera frugiperda)
Symptom/Damage: Larvae attacks and destroys the whorl of the host plant. Symptoms appear as saw-dust frass when young; pellets at late instars. Severe infestation may appear like hail-storm damage.

Control
Considered measures for FAW management in Kenya include:
1. Appropriate planting practices
2. Mechanical control
3. Restricting movement of infested plant materials
4. Use of pesticides
An integrated management approach (combining several intervention measures) is recommended.
1. Appropriate planting practices
• Plant early and adhere to regional planting calendar
• Early planting allows maturity of maize before high pest population build-up
• Avoid planting of new maize crops near heavily infested plants.
2. Mechanical control
 Handpick and squash egg masses
 Pick and crash caterpillars or drown them in soapy water. Killing one caterpillar prevents more than 1500 new caterpillars which would have emerged.
3. Restricting movement of infested plant materials such as green maize and stover.
4. Use of pesticides
The most recommended Insecticides for control of FAW include the following:

• Choice of appropriate insecticides is vital

• Spraying should be done late in the evening or very early in the morning when the larvae are active (not hiding).
• Target application to the plant whorls (funnel) and the 3 lower leaves.
• Combination of pesticides with other methods of control minimizes chances of resistance development.

Armyworm

Symptoms/Damage: The larvae feeds on all types of grasses and early stages of cereal crops, leading to excessive consumption of the nearby vegetation, especially the leaves of cereal crops and grasses. Outbreaks tend to occur during rainy season after periods of prolonged drought with devastating effects on farmland and pasture.

Control
• As for Fall armyworm

Maize stalk borer

Symptom/Damage: Young plants have pinholes in straight lines across the newest leaves. The larvae then moves into the stem and damages it.

Maize stalk borer

Control

·         Early planting

·         Field sanitation

·         Crop rotation

·         Use Push-pull technology

·         Apply recommended insecticides eg Bulldock, Thiodan or Ambush

Cutworms

Symptom/Damage: Cutworms cut maize seedlings at or a little below ground level, make small holes along the initial leaves, or remove sections from the leaf margins.

Control

·         Spray Bestox 10 EC when soils are moist or apply FASTAC

Termites

Symptom/Damage: Termites attack the roots and stems about 3 months after planting. Severely damaged plants wither, lodge and fall on the ground. As plants mature, the amount of damage increases. Infestation is particularly serious in dry season.

Termites

Control

·         Destroy termite nests, remove and kill the queen.

·         Apply termiticides 

Rodents

Symptoms/Damage: Most common damage is inflicted to the maize cobs. Direct damage to maize grains is by gnawing and feeding. Indirect damage is by spoilage, thus rendering the grans unpalatable for human consumption.

Control

·         Use rat traps

·         Cultural approaches eg by planting Gliricidia sepium tree (rat killer)

·         Use rat poison (chemical control)

·         Biological control (use predators like cats)

Maize Weevil

Symptom/Damage: Larvae bores thin tunnels beneath the seed coat leaving circular holes on the surface of the grain.

    weevils

Control

·         Early harvesting

·         Clean and dust the store well before use with Actellic super or Sumicombi.

·         Dust the shelled maize with an insecticide like Actellic super, Skana Super dust.

The Larger Grain Borer

Symptom/Damage: Attacked maize grains lose all their contents and are not fit for consumption.

                    LGB Damage                     LGB

Control

·         Leave maize to dry completely in the field before stoking.

·         Dust maize with Actellic super, Sumicombi, Skana super dust, Spinter dust or Super Malper dust

·         Spray stores with recommended insecticide.

·         Fumigants –Restricted to lage grain handlers eg NCPB.

(i)Maize Smuts (Common and Head Smut)

The first symptoms become evident when tassels and cobs (ears) appear.

                     Head smut

 Common smut (Boil smut, Blister smut)

Symptoms

·         Large white to black galls on stalks, tassels and ears.

·         Masses of black spores are released if galls are opened.

Control

·         Use certified seeds

·         Crop rotation

·         Plant resistant varieties

·         Rogue and destroy by burning the affected plants.

(ii)Maize Lethal Necrosis Disease (MLND)

Symptoms

·         Chlorotic mottling which starts from the base of the leaf and extends towards tip.

Control

·         Observe closed season

·         Crop rotation/diversification

·         Seed treatment to control vector

·         Plant tolerant/resistant varieties

(iii) Maize Streak Virus

The virus is transmitted by leafhoppers.

Symptoms

·         White yellowish narrow streaks on the leaves, running parallel along the leaves.

·         Plants infected at early stage usually do not produce any cobs.

Control

·         Use certified maize seed

·         Plant tolerant/resistant varieties

·         Rogue infected plants early.

·         Crop rotation.

(iv)Leaf Blight

Northern Leaf Blight

Disease development is promoted by prolonged wetness on foliage or extended dew.

Symptoms

·         Elongated small yellow dots between veins that later become brownish with reddish to purplish brown borders. The spots may join together and result in blighting of entire leaves.

Control

·         Use certified seeds

·         Plant tolerant/resistant varieties

·         Remove crop residue after harvest

·         Crop rotation.

(v)Grey Leaf Spot

The disease is favoured by prolonged periods of high relative humidity.

Symptoms

·         Similar to leaf blight but the spots are much narrower.

Control

·         As for leaf blight.

(vi)Rust

Symptoms

·         Brown postules on leaves

Control

·         Plant resistant varieties

·         Crop rotation

·         Deep ploughing of crop residue

The stage of maturity is determined by yellowing of the leaves, yellow dry papery husks, and hard grains with a glossy surface.

Often, the crop is left to dry in the field until the moisture content of the grain has fallen to 15-20%. 

Harvesting can start 10 -15 days after physiological maturity.

Harvest by de-husking.

Depending on the Agro Ecological zone and the variety, with good management, average yields in Western Kenya range from 3-6 metric tons per hectare.

High moisture content with high temperatures can cause considerable damage such as infestation by weevils and grain borers and the development of aflatoxin, thus making the product unsuitable for consumption.

To determine whether the maize is fully dry, test the moisture content by taking a few grains and trying to crush them by teeth. Below 13% moisture level, the grains are extremely hard and almost impossible to crush this way.

If necessary, the grains can be further dried in the sun. The grains should be spread out on clean tarpaulins, not on soil, to avoid aflatoxin infection.

Storage of clean, dry grains in airtight bags (hermetic bags) or metallic silos is recommended. Storage of grains in sisal or jute bags indoors will require fumigation or the use of insecticides.

Storage bags should be placed on pallets or raised platform.
Protect the bags or metallic silos from moisture absorption, insects and rodents.