Complete Farming Guide
Cassava Farming Guide
Manihot esculenta
330 million tonnes — food security for 800 million people
Cassava is the lifeline crop of the tropics, feeding over 800 million people primarily in sub-Saharan Africa, Southeast Asia, and Latin America. It thrives where other crops fail — in poor, acidic soils with erratic rainfall. Cassava's extraordinary drought tolerance comes from its ability to shed leaves during water stress and regrow them when rains return. The roots store dense calories (primarily starch) that can remain in the ground for up to 2 years, functioning as a "living food bank." However, cassava roots deteriorate within 24-48 hours of harvest, making post-harvest processing a critical challenge.
Quick Facts
Growing Season
Year-round (tropics)
Growth Period
9-18 months
Optimal Temp
25-35°C (77-95°F)
Water Needs
1000-1500mm (drought tolerant)
Top Producer
Nigeria
Yield / Acre
4-12 tonnes/acre (varies enormously)
Cassava Growth Stages — What to Do at Every Stage
Establishment (Sprouting & Rooting)
Months 1-2What to do
Plant stem cuttings (stakes) 20-30cm long at 1m x 1m spacing, angled or horizontal in well-drained soil. Use healthy, mature stems (8-12 months old) from disease-free mother plants. Plant at the beginning of the rainy season for best establishment.
Watch for
Poor sprouting from old or diseased stakes. Termite damage to planted stakes — treat with appropriate insecticide if termite pressure is high. Waterlogging kills young plants rapidly.
Canopy Development
Months 3-5What to do
Weed 2-3 times during this period — weed competition in the first 3 months is the #1 yield reducer in smallholder cassava. Apply NPK fertilizer (60-40-80 kg/ha) if available. Intercrop with short-cycle crops (maize, beans, groundnuts) during this window.
Watch for
Cassava mosaic disease (CMD) symptoms — yellow-green mosaic pattern on leaves, leaf curling and distortion. Whitefly populations building on leaf undersides. Remove and burn CMD-infected plants immediately to prevent spread.
Root Initiation & Bulking
Months 6-10What to do
Roots are now forming and filling with starch. Avoid disturbing the root zone. If a dry season occurs, cassava will shed leaves and enter dormancy — this is normal and the plant will recover when rains return. Do not irrigate during leaf shed if rainfed.
Watch for
Cassava brown streak disease (CBSD) — yellow patches or blotches on leaves AND brown, corky necrotic patches inside the roots that make them inedible. CBSD is the most devastating cassava disease because root damage is not visible until harvest.
Starch Accumulation
Months 11-15What to do
Roots are accumulating maximum starch. Harvest timing depends on end use: for fresh consumption, harvest at 9-12 months (lower starch, better texture). For starch extraction, harvest at 12-18 months (maximum starch content). Test starch content by cutting roots — dense, white flesh indicates high starch.
Watch for
Root rot (Phytophthora, Fusarium) in waterlogged soils. Roots become fibrous and woody if left too long in the ground (beyond 18-24 months). Cassava green mite damage — stippled, yellowish leaves.
Harvest & Post-Harvest
Months 12-18+What to do
Harvest by cutting stems to 20-30cm stubs, then carefully uproot. CRITICAL: Cassava roots deteriorate within 24-48 hours of harvest due to post-harvest physiological deterioration (PPD) — blue-black vascular streaking makes roots unmarketable. Process (peel, soak, dry, or ferment) within 24 hours.
Watch for
Blue-black vascular streaking in fresh roots indicates PPD has begun. Cyanogenic glucosides (HCN) in bitter varieties — proper processing (soaking, fermenting, drying) is ESSENTIAL to remove cyanide before consumption. Sweet varieties have lower HCN but still require cooking.
Common Cassava Diseases — Identification Guide
Cassava Mosaic Disease (CMD)
Cassava mosaic geminiviruses
What you will see
Yellow-green mosaic pattern on leaves, with light green or yellow patches interspersed with normal dark green tissue. Severe strains cause leaf distortion, curling, and reduction in leaf size. Stunted plants with reduced root yield — losses of 20-95% depending on strain and time of infection.
Conditions that favor it
Transmitted by whitefly (Bemisia tabaci) and through infected stem cuttings. The most important disease of cassava in Africa. Use of infected planting material is the primary spread mechanism. Resistant varieties (e.g., IITA improved varieties) are the best defense.
Cassava Brown Streak Disease (CBSD)
Cassava brown streak viruses (CBSVs)
What you will see
Yellow patches or blotches on mature leaves with feathery margins along leaf veins. Stem lesions — dark brown, elongated streaks on stems. The most devastating symptom is HIDDEN: brown, corky necrotic patches inside the root that make it inedible. You cannot tell a root is infected until you cut it open.
Conditions that favor it
Transmitted by whitefly and through infected planting material. Expanding rapidly across East and Central Africa, now threatening West Africa. Considered the single greatest threat to food security in cassava-dependent regions.
Cassava Bacterial Blight (CBB)
Xanthomonas axonopodis pv. manihotis
What you will see
Angular, water-soaked lesions on leaves that become brown and dry. Gum exudation (sticky, amber-colored ooze) on stems. Wilting and die-back of shoot tips. Severe infections cause complete defoliation and stem die-back. Can be confused with drought stress.
Conditions that favor it
Warm, humid conditions with frequent rain. Spread through contaminated planting material, rain splash, and cutting tools. Worst during the rainy season. Use clean planting material and disinfect cutting tools between plants.
Cassava Anthracnose Disease (CAD)
Colletotrichum gloeosporioides f. sp. manihotis
What you will see
Sunken, dark brown cankers on stems, especially at nodes. Cankers may girdle the stem, causing die-back above the infection point. Young shoots wilt and die. Leaf spots are small, circular, and brown with concentric rings.
Conditions that favor it
Warm, humid conditions with heavy rainfall. Stressed plants (nutrient-deficient, drought-weakened) are more susceptible. Spreads through rain splash and contaminated tools.
Root Rot Complex
Phytophthora spp., Fusarium spp., Botryodiplodia
What you will see
Soft, watery decay of roots in the ground — roots feel mushy when pressed. Foul-smelling rot. Above-ground: wilting despite adequate soil moisture, yellowing leaves, and sudden plant collapse. Most damage occurs underground and is not noticed until harvest.
Conditions that favor it
Poorly drained, waterlogged soils. Heavy clay soils with poor structure. Continuous cassava cropping without rotation. Harvesting in the wet season creates wounds that facilitate rot.
Common Cassava Pests — Identification & Damage
Whitefly (Bemisia tabaci)
Damage
The single most important pest of cassava — not for direct feeding damage, but as the vector of both CMD and CBSD viruses that cause devastating yield losses. High whitefly populations also cause sooty mold from honeydew excretion, reducing photosynthesis.
How to identify
Tiny (1mm) white-winged insects on leaf undersides. Disturbing the plant causes a cloud of white flies. Yellow nymphs (immobile) on leaf undersides. Check young, expanding leaves at the shoot tip — this is where adults prefer to feed and lay eggs.
Cassava Green Mite
Damage
Feeds on leaf undersides, causing yellow stippling that progresses to leaf chlorosis, distortion, and premature leaf drop. Severe infestations give the canopy a yellow-green, sickly appearance. Yield losses of 13-80% reported in dry conditions when mite populations explode.
How to identify
Very tiny (0.3mm) pale green to yellow mites, barely visible without a hand lens. Found on the undersides of young leaves near the growing tip. Look for tiny white cast skins and fine webbing. Symptoms are most visible during dry seasons.
Cassava Mealybug
Damage
Feeds by sucking sap from growing tips, causing leaf curling, stunting, and a characteristic "bunchy top" appearance where internodes are shortened. Severe infestations cause complete dieback of shoot tips. Yield losses of 30-60% in outbreak years.
How to identify
White, waxy-coated insects (2-3mm) found in clusters on shoot tips, leaf axils, and undersides of leaves. Plants look like they have been dusted with flour at the growing points. A white, waxy trail on stems indicates mealybug presence.
Termites
Damage
Feed on the woody stems and roots of cassava, both in the field and on stored stems. Attack planted stakes, hollowing them out and preventing sprouting. Root feeding reduces yield and creates entry points for rot organisms.
How to identify
Look for mud tubes (shelter tubes) on stems and at the soil surface around the plant base. Break open dead or hollow-sounding stems to find termite galleries. Most damage occurs during dry seasons when termites seek moisture from cassava roots.
Variegated Grasshopper
Damage
Large grasshoppers that feed on cassava leaves, sometimes defoliating entire fields during outbreaks. Each grasshopper consumes 5-10 square cm of leaf per day. Nymphs aggregate in large groups and systematically strip leaves from plants.
How to identify
Large (45-55mm), brightly colored grasshoppers — yellow and black with blue-green hind legs. Found resting on stems and leaves during the day. Nymphs are smaller and darker. Most damaging during the dry-to-wet season transition when grasshopper populations peak.
Cassava Nutrient Management — NPK Guide
Nitrogen (N)
40-60 lb N/acre (cassava is relatively efficient)
Phosphorus (P)
20-40 lb P2O5/acre
Potassium (K)
60-100 lb K2O/acre — cassava is a heavy potassium user for root starch production
Application Timing
Apply NPK at 1-2 months after planting when plants are established. In low-input systems, prioritize K > N > P. Cassava extracts large amounts of potassium from the soil — returning crop residues (leaves, stems) to the field helps maintain K levels. Organic matter (compost, manure) is highly effective.
Cassava Irrigation Schedule
Total Water Requirement
1000-1500mm but cassava survives on as little as 500mm
Critical Stages
The first 3 months of establishment are the most water-sensitive. After canopy closure, cassava is remarkably drought tolerant — it sheds leaves to conserve water and regrows when rains return. Root bulking benefits from consistent moisture but the crop does not die from drought.
Irrigation Frequency
Rainfed production is the norm for 90% of global cassava. If irrigating, focus on the establishment phase (first 3 months). Cassava is often planted at the start of the rainy season to maximize natural rainfall during establishment.
Cassava Economics — Cost, Yield & Profit
Cost per Acre
$100-300/acre (low-input crop)
Yield per Acre
4-12 tonnes fresh roots/acre
Revenue per Acre
$200-800/acre (fresh); $500-1,500/acre (processed starch/flour)
Profit per Acre
$100-500/acre
Regional Context
Cassava economics are driven by the processing chain. Fresh roots have the lowest value but also lowest processing cost. Dried chips, high-quality cassava flour (HQCF), and industrial starch command premium prices but require processing infrastructure. The 24-48 hour post-harvest deterioration window is the single biggest constraint to cassava commercialization. Mobile processing units and waxing technologies are extending shelf life. In Thailand and Vietnam, cassava is primarily an industrial crop for starch and ethanol, with higher yields (10-12 t/acre) and commercial processing chains.
Frequently Asked Questions — Cassava Farming
Why do cassava roots go bad so quickly after harvest?
Cassava roots undergo Post-harvest Physiological Deterioration (PPD) within 24-48 hours of harvest. This is not microbial rot — it is the root's own wound response. When the root is detached from the plant, damaged cells release enzymes that cause rapid blue-black discoloration of the vascular tissue (the streaks you see when cutting deteriorated roots). This makes roots unmarketable and unpalatable. Management strategies: (1) Harvest only what you can process or sell within 24 hours, (2) Leave roots in the ground as a "living food bank" until needed, (3) Process immediately into dried chips, flour, or garri (fermented product), (4) Waxing freshly harvested roots extends shelf life to 2-4 weeks, (5) Store in moist sawdust or sand at 0-5°C for 1-2 weeks. Varieties with reduced PPD are being developed through breeding programs.
Is cassava safe to eat? What about cyanide?
Cassava contains cyanogenic glucosides (linamarin and lotaustralin) that release hydrogen cyanide (HCN) when the tissue is damaged. "Bitter" varieties have high HCN levels (100-500 mg/kg) and MUST be properly processed before eating. "Sweet" varieties have lower levels (under 50 mg/kg) and are safe after normal cooking. Proper processing to remove HCN includes: (1) Peeling — the peel contains the highest HCN concentration, (2) Soaking in water for 3-5 days (fermentation breaks down cyanogenic compounds), (3) Sun-drying grated cassava (HCN volatilizes), (4) Boiling — always in open pots to allow HCN gas to escape. Traditional processing methods (garri, fufu, tapioca) have been refined over centuries to reduce HCN to safe levels. Never eat raw cassava, especially bitter varieties.
How do I prevent cassava mosaic disease?
Cassava Mosaic Disease (CMD) prevention starts with planting material. Use ONLY healthy, disease-free stem cuttings from certified sources or from CMD-free mother plants. Select planting stakes from plants that showed no mosaic symptoms throughout their growth. Use CMD-resistant varieties developed by research programs (e.g., IITA, CIAT, national programs) — varieties like TME 419, IITA-TMS-IBA30572, and regional equivalents combine resistance with good yield. Additional measures: (1) Remove and burn CMD-infected plants immediately (roguing), especially in new fields, (2) Manage whitefly populations through clean field practices and timely planting, (3) Avoid planting new cassava adjacent to infected fields, (4) Do not carry stakes from infected to clean areas. Where CMD-resistant varieties are grown, yield losses can be reduced from 50-95% to under 10%.
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