Agriseeds Soyabean

Soyabean is a legume plant with many cultivars, Agriseeds has devoloped Soyabean Lundi with the following characteristics:

Indeterminate

Early maturity (90-110 days)

Brown hilum seed

Good shuttering period

Good tolerance to Rust and Frog Eye disease

Good pod clearance for easy combing

High yielding potential of +4mt/Ha

Soyabean Lundi Production

Climatic Requirements

High rainfall areas of above 600mm.(Zimbabwe ecological regions i,ii & iii)

Average temperature of 25 Degrees Celcius

Moderate wind speed

Aspect North facing slope

More sunlight hours, 12hrs/day

Soil Requiremnts

Heavy clay soils

Loam soils

Well drained soils

pH 6-7

Land Preparation

Deep plough

Harrowing

Basal fertiliser application as per soil analysis results. Compound L, S or D.

Herbicide application, preemergence

Planting

Planting time- Mid November to 20 December

Plant only when soil is moist to field capacity

Use innoculant or Rhizobium

80-120kg/hectare seed

Row spacing: 45-50cm

Plant spacing: 4-7cm

Plant depth: 5cm

Pests and Disease Management

It is important to scout for pests regularly throughout the growing season.

Pest monitoring should be done weekly and then twice a week from flowering onwards.

The best time to check crops is in the morning (between 7am -9am) when insects are most active.

There are a number of diseases that affect soybean.

Fungal Diseases

Soyabean Rust

Symptoms: infected leaves have small tan dark brown or reddish brown lesions. From lesions, small raised pustules or bumps can occur on the lower surface of the leaves. Severe infection can lead to premature defoliation and cause high yield losses. It is spread by wind.. Early detection is key. Follow with use of fungicides such as Folicure at first appearance to reduce damage.

Downy Mildew

Symptoms: yellowish green spots (lesions) with undefined margin appear under the leaf surface. The lower surface has greyish tufts. Severely infected leaves die and fall off. Conditions: survives between crops in infected crop residues or on seed. Development of disease is favoured by cool, moist weather and narrow row spacing. Control: plant disease-free and resistant varieties, rotate crops and clear tillage.

Damping Off and Anthracnose

Symptoms: Seed-borne diseases caused by several fungi. The infected pools or stems at first show irregularly shaped, reddish brown or dark brown area that is later covered by tiny black spines. the diseases cause rotting of seeds before emergence from soil or death of seedlings after emergence. When seeds emerge from the soil, they are often brown, sunken cankers on leaves which can be covered by pink spores in moist weather. Conditions: Favours by cool weather.

Frogeye Leaf Spot (Cercospora Sojina)

Symptoms: consist of brown circular or irregular spots with narrow reddish brown margins on the lead surfaces. When mature seeds are infected, lesions can develop on stems and pods. Infected seeds may show dark grey or brown discolouration in small specks to large blotches. Conditions: The fungus survives in infected crop residues and in infected seeds. Control: tillage and crop rotation are effective means of reducing the population from season to season. Consider a resistant variety if the field has a history of the disease.

Red Leaf Blotch

Symptoms: in the first stage of the disease, lesions appear on the unifoliate leaves associated with the primary leaf vein. At this point, the disease is easily confused with other diseases or cultural conditions affecting soybeans. Later, dark red spots with reddish brown and dark borders on the lower leaf surfaces develop on trifoliate leaves.

Bacterial Diseases

Bacterial Blight

Symptoms: when plants are infected early in the season they may be stunted and dies. Symptoms in the later stages consist of angular lesions which begin as small water-soaked yellow to light brown spots on the leaves. The centres of the spots will turn a dark, reddish brown to block or dry out. Eventually, lesions fall out of the leaf. The disease spread in windy rainstorms and during cultivation while the foliage is wet. Conditions: The bacteria is carried over in crop debris and infected seeds. Control: crop rotation, allow crop residue to break down.

Wildfire

Symptoms: light brown necrotic spots of variable sizes, surrounded by broad yellow halos on the leaves. In damp weather, the spots enlarge forming large dead areas on the leaf. Wildfire disease is commonly associated with bacterial

Sclerotinia Stem Rot or White mould

Symptoms: plants die down after bloom with leaves remaining attached. A white cottony mould forms in the foliage and lower leaves. Conditions: cooler than normal temperature, high humidity. White mould fungus survives between crops as sclerotia. Control: crop rotation

Cercospora Purple Seed Stain and Leaf Blight

Symptoms: soybean seed, pods, leaves and stems are all affected by the disease. The most easily distinguished symptom is pink to purple discolouration. Conditions: Control: disease-free seed, crop rotation, clean plough down of infected crops, application of certain foliar fungicides will help with certain phases.

Viral diseases

These can be transmitted through aphids, beetles and whiteflies. Most viral diseases result in foliar symptoms such as mosaic or mottling, thickening of older leaves. puckering, leaf distortion, a severe reduction in leaf size and stunting.

Common Insects

Beneficial insects keep insect populations below economically damaging levels. Sometimes severe outbreaks occur making control necessary. Soybean plants can tolerate some damage to leaves particularly before flowering but direct damage to pods or heavy defoliation (leaf loss) post flowering can result in yield losses. It is important to become familiar with the common types of insects and types of damage at different parts of the growing season.

Spider Mite

Minute red, black or brown arachnids that attack plants. Treatments applied too early may damage beneficial insects. Conditions: dry, hot conditions encourage mites Control: Pyrethrum paralyzes mites.

Soybean aphids

During the flowering stage plan to monitor symptoms such as stunted growth and fewer pods. They are a vector in a number of viruses Conditions: occur sporadically during warm, dry periods. Control: avoid water stress to your plants. Beneficial insects may control aphids. Chemical control: use registered insecticides.

Green stink bugs

This is a flattened, shield-shaped bug that is bright green in colour. It feeds on pods using its piercing-sucking mouthpart causing pod damage.

Cutworm

Larvae are usually dark grey to brown with a smooth, wavy appearance and are found 20-50mm under the soil. Control: chemically using synthetic pyrethroids

Soybean Cyst Nematodes

Symptoms: severely infected plants are stunted and yellow. Yellowing resembles potash or nitrogen deficiency. Conditions: things like equipment that move the soil move nematodes. The disease favours low potash fertility. It is most severe in sandy soils. Continuous soybean production ( 2 years in a row) also induces nematodes. Control: Crop rotation, using resistant cultivars and rotating with a non-host crop

Crop Stage	Chemical	Rate/ha	Application
Herbicides(pre-emergent)	Metribuzin 480SC	600ml-1.2lt/ha	Apply pre-emergent for broad leaf and some annual grasses(tank mix ) with a suitable grass herbicide.
	Dual Magnum 960EC	07-1.5lt/ha	Apply pre-emergent for annual grass weeds and a few broadleafs including yellow nutsedge suppression. (tank mix with Metribuzin for improved broadleaf control)
	Lasso/Alachlor 48EC	2.8-4lt/ha	Apply pre-emergent for annual grass weeds and a few broadleafs including yellow nutsedge suppression(tank mix with Metribuzin for improved broadleaf control).
	Bateleur gold	0.7-1.7lt/ha	Apply pre-emergence for both broadleafs and annual grasses
	Frontier Optima	0.6-1.2lt/ha	Apply pre-emergent for control of annual grasses, suppression of yellow nutsedge and wandering dew. Can be tank mixed with broadleaf herbicide)
	Acetochlor	0.5-1lt/ha	Apply pre-emergent for annual grass weeds and a few broadleafs including yellow nutsedge suppression(tank mix with Metribuzin for improved broadleaf control).
	Authority 480SC	600mls700mls/ha	Apply pre-emergent for control of sedges including some broad leafs. Tank mix with a suitable annual grass herbicide.
	Prowl CS	2.3-3.3lt/ha	Apply as pre-emergence for the control of Shamva(Rottbollea spp), annual grasses and a few broadleafs.
	Clomazone 4 EC	1.5-2.3lt/ha	For the control of annual grasses, volunteer, (wheat and maize), wandering dew and broadleaf weeds.
Herbicides(post-emergent)	Agil 100EC	0.5-2lt/ha	Apply as post emergent(over the top-OTT) for control of annual and perennial grasses. Increase rate for perennial grasses.
	Fusilade forte	0.8lt-6.5lt/ha	Apply as post emergent(over the top-OTT) for control of annual and perennial grasses. Increase rate for perennial grasses.
	Basagran 480	2.5-3.0lt/ha	Apply as post-emergence for the control of broadleaf weeds and yellow nutsedge. Apply after the second trifoliate leaf stage of crop. (Do not mix with grass herbicides)
	Pursuit(Hammer)	500-700mls	Apply as pre or post emergent(over the top-OTT) for control of a range of a broadleaf herbicides.(Add pursuit booster when applying post emergent). The lower rate is for preemergent applications.
	Classic(chlorimuronethyl)	30gm/ha	Applied post emergence for the control of broadleaf weeds, suppression of yellow nutsedge, wandering dew and Mexican clover
Insecticides	Lambda-cyhalothrin	100150mls/ha	Apply over crop row for cutworm control
	Carbaryl 85WP	1kg/ha	Apply at least 2 sprays for semi-looper control
	Dichlorvos	500mls/ha	Apply at least 2 sprays for semi-looper control
Fungicides	Opera	500mls/ha	Rust, Red Leaf blotch and Frog eye, apply at 50 days after crop emergence and repeat application 21 days later, when necessary.
	Folicur	500mls/ha	Rust, apply at 50 days after crop emergence and repeat application 21 days later, when necessary.
	Shavit	500mls/ha	Rust, apply at 50 days after crop emergence and repeat application 21 days later, when necessary.
	Tilt	500mls	Rust, apply at 50 days after crop emergence and repeat application 21 days later, when necessary.
	Score	375mls/ha	Rust, apply at 50 days after crop emergence and repeat application 21 days later, when necessary.
Nematodes			Soyabean are hosts to root knot nematodes and therefore should not be grown in rotation with tobacco, tomatoes, potatoes and sunflower.