Fenugreek Pests And Diseases – Control Measures
Introduction to fenugreek pests and diseases
Fenugreek is a herbaceous annual plant grown for its seeds and leaves. It is one of the oldest medicinal plants in the world. Fenugreek is cultivated throughout and other parts of the world as a leafy vegetable, condiment, for medicinal and fodder purposes. Fenugreek is rich in minerals, protein, and vitamins A and C. If you are planning for commercial Methi or Fenugreek farming, you must be aware of the common pests and diseases of Fenugreek crop.
A step by step guide to Fenugreek pests, diseases, and their control
Fenugreek is a herbaceous annual plant in the family Fabaceae has grown for its leaves and seeds which are used as a herb or spice. The fenugreek plant has a single stem or may be branched at the stem base. This plant has an erect growth habit and a strong, sweet aroma. The plant leaves are small and trifoliate with oval leaflets which are green to purple. The fenugreek plant produces solitary pale white or purplish flowers and a straight or occasionally curved yellow pod that houses the seeds. Between 10 and 20 seeds are produced per pod and they are small, smooth, and brown, each divided into 2 lobes. Fenugreek can reach a height of about 60 cm and as an annual, survives only one growing season.
Conditions for fenugreek cultivation
- Fenugreek or Methi is propagated from seed and it does not withstand transplanting. It should be direct-seeded to a depth of 1–2 cm allowing 7.5 cm between individual plants and 20–45 cm between rows. It may also be spread by broadcasting. The important aspect of fenugreek cultivation is keeping the bed free from weeds. Beds must be weeded regularly to prevent competition with the developing plants. The Fenugreek plants will benefit from additional irrigation if rainfall is not adequate. Also, the productivity of fenugreek grown for seed will be increased with the addition of potash and phosphate fertilizer.
- For sowing one-acre land, a seed rate of 12 kg/acre is used. The land is prepared by ploughing thrice and beds of uniform size are prepared. Broadcasting the seed in the bed and then raking the surface to cover the seeds is normally followed. But, line sowing is advocated in rows at about 20 to 25 cm apart which facilitates the intercultural operations.
- Sowing in the plains is generally taken up in September to November while in the hills, it is grown from March. Approximately 20 to 25 kg of seed is required for one hectare and the seed takes about 6 to 8 days to complete its germination.
- Besides 15 tonnes of farmyard manure, a fertilizer dose of 25 kg Nitrogen, 25 kg Phosphorus, and 50 kg Potash per ha is recommended. To obtain more successful leafy growth, nitrogen must be applied after each cutting.
- You will need to minimize weeds around this plant for good production. However, you want to be careful not to disturb the root system of the fenugreek.
- Since this plant is quick to germinate, establish, and set seeds it often doesn’t develop deep and entrenched roots. So, pulling weeds can disturb the delicate roots of fenugreek. If weeds emerge, you can clip them at the head with scissors to keep them in check until you harvest your fenugreek. This plant only needs some well-aged compost to grow well. You don’t want to add any kind of fast-acting fertilizer for good production. Excess nitrogen will stunt these plants.
- If plants need a mid-season fertility boost, compost tea is your best bet to stimulate growth. Just add 1 part compost tea to every 8 parts water in your watering can and moisten the soil like usual. You can also use low nitrogen, high beneficial bacteria fertilizers like fish emulsion to perk plants up in extended hot or dry periods.
- First irrigation is given immediately after seed sowing and subsequent irrigation is applied at 7 to 10 days interval.
Major pests and diseases of Fenugreek and their control
Fenugreek diseases are mainly classified into two broad groups. They are biological and physiological diseases based on their pathogenicity. Physiological diseases occur due to mineral deficiencies and biological diseases occur due to fungal, bacterial, viral, and insect infections. These diseases have been reported to be associated with a considerable lowering of forage and seed yield in fenugreek which is a serious agronomic concern. Now, let us get into the common diseases and pests of Fenugreek crop.
Fungal diseases – The two most common fungal diseases infecting fenugreek are Cercospora leaf spot and powdery mildew.
Cercospora leaf spot
Symptoms – Circular sunken lesions with chlorotic halos on leaves; necrotic areas on leaves; discolored areas on pods. Cercospora leaf spot is another potentially damaging fungal pathogen that can reduce your crop of leaves and damage seed pods.
Growing fenugreek in temperatures that stay consistently below 70ºF is the best preventative for avoiding this fungal disease. By using certified seeds from a reputable source or pre-treating seeds with fungicides can help. Also, in extreme cases spraying fungicides can be necessary. Good crop rotation is also key and doesn’t plant fenugreek in areas where other legumes have been for at least three years to reduce risks.
Symptoms – Discoloration of the vine at the soil line and cankers on the stem can spread upwards; leaves wilt and drop from the plant; numerous small black sclerota develop in affected tissues and used to diagnose the disease.
Organic soil amendments such as the addition of neem cake or manure can be used to reduce levels of inoculum in the soil. Charcoal root rot is aptly named after the appearance of the disease as it makes its way up the inside of the plant stem to its leaves. You’ll need to cut open the stem to see the damage. But, the appearance of desiccation of the outer parts is usually what makes people notice the plant has a problem. This plant disease is most commonly discussed about soybeans but can be a problem for other legumes, including fenugreek, as well.
Fungicides are ineffective in treating pathogen. So, if you suspect an infection, your best bet is to pull impacted fenugreek plants and avoid planting legumes in that area for at least three years. Again though, prevention is possible by growing fenugreek in cooler temperature levels and keeping the soil consistently moist. In ideal conditions, this pathogen is much less likely to get a foothold in the garden. Also, amending soil with well-aged compost and neem meal or cake might dilute and suppress some development of the pathogen.
Yellow mosaic disease
- Mosaic virus disease with symptoms of vein clearing, severe molting, and leaves curled at the margin and reduced leaf size.
- Pods, if formed, are very small, curled with thin and shrunken seeds.
- Transmission and favorable conditions
- The disease is transmitted in a semi-persistent manner by the aphid.
- Aphids are more active in warm conditions and increase their population as well as spread the virus.
Symptoms – It usually appears late in the season. Powdery white growth can be seen on both the surfaces of the plant leaves. It also appears on the above-ground plant parts.
Management – The disease is controlled by dusting sulphur at 25 kg/ha or spraying Wettable sulphur 0.25 percent at 20 days interval.
Root rot is a serious disease and can be controlled by drenching carbendazim 0.05% first at the onset of the disease and another after one month.
Management -To protect the crop from root rot, as a preventive measure do soil application of Neem Cake by 60kg/acre. Also treat seeds with Trichoderma viride by 4gm/kg of seed. If infestations of root rot, observed in the field to control, drenched the soil with Carbendazim by 5gm/liter of water or Copper oxychloride by 2gm/liter of water.
Disease symptoms – The emerged seedlings exhibit water-soaked discoloured, soft basal rot of the stem due to the death of cortical tissues. The rotted seedlings emit bad odour, the whole seedling topples over.
High humidity, high soil moisture, cloudiness, and low-temperature levels below 24°C for a few days are ideal for infection and development of the disease. Crowded seedlings, dampness due to high rainfall, and excess of soil solutes hamper plant growth and increase the pathogenic damping-off.
Flea beetles are about the most troublesome pest in my garden. They are so tiny and fast that it’s difficult to control them. Luckily, they don’t tend to do much damage to healthy plants. In the case of fenugreek though, the leaves are small and so even a little flea beetle damage can make the plant aesthetically unappealing.
Management – Honestly, the only answer I know that works every time is growing fenugreek under floating row covers. Some gardeners also use a 70% mix of neem oil spray with some success. However, you have to reapply every 7-10 days for continued protection. To reduce the overall population of flea beetles in your garden, there are also things you can do such as hanging sticky strips during mating season, using tape to collect the beetles from the undersides of leaves in the early morning, and introducing beneficial nematodes into your garden soil to control the larvae.
Symptoms – Small soft-bodied insects on the underside of leaves and stems of the plant; usually green or yellow, but may be pink, brown, red, or black depending on species and host plant; if aphid infestation is heavy it may cause leaves to yellow and distorted, necrotic spots on leaves and stunted shoots; aphids secrete a sticky, sugary substance called honeydew which encourages the growth of sooty mold on the plants
Management – If the aphid population is limited to just a few leaves then the infestation can be pruned out to provide control, and check transplants for aphids before planting; use tolerant varieties if obtainable; reflective mulches such as silver-colored plastic can deter aphids from feeding on plants; sturdy plants can be sprayed with a strong jet of water to knock aphids from plant leaves; insecticides are generally only required to treat aphids if the infestation is very high and plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are the best methods of control; always check the labels of the products for specific usage guidelines before use.
Mineral nutrient deficiency – Physiological diseases have been reported to be associated with early death and loss of forage and seed yield in fenugreek. Fenugreek is reported to be sensitive to mineral deficiencies. It has been suggested that yellowing of some fenugreek plants under field conditions is connected to probable mineral deficiencies, in particular to elements like boron, magnesium, and manganese or potassium deficiency.
Integrated Pests and Diseases Management (IPM) strategies for Fenugreek crop
- Avoid monoculture and follow crop rotation for control of both insect pests and pathogens.
- Soil solarization of nursery beds should be done to reduce the inoculums level of pathogens in the soil.
- Resistant or tolerant varieties can be used for cultivation.
- Weeds can be alternate hosts for both pests and pathogens, so it should be destroyed
- Plant density and row width can be altered to allow escape from pests and diseases.
- Destruction of infected plant material should be done during field scouting.
- Control ants that guard aphid colonies in plants from predators by placing sticky bands around the trunks.
- For seed-borne fungal diseases selection of healthy seeds as planting material provides effective control.
Freshly harvested Fenugreek leaves.
For the vegetable purpose, harvesting of the crop can be started from 20 to 25days after sowing while for grain purpose, harvesting is done 90 to 100days after sowing. For grain purpose, harvest when lower plant leaves turn yellow and start shedding and pods turn to yellowish colour. Use sickle for harvesting purposes. This fast-growing annual will produce leaves that are ready to harvest within just 20-30 days of sowing.
Trim the leaves carefully, snipping off the top third of mature stems, and allowing the rest to continue growing. This will also encourage branching, which will increase flowering and seed production later on.