Introduction to Ginger Pests and Diseases
Ginger is the earliest known oriental spices, belonging to the Zingiberaceae family. Though the whole plant is refreshingly aromatic, the underground rhizomes of this crop are valued as spice. It is one of the generally consumed dietary condiments in the world and has high medicinal properties.
A Step by Step Guide to Common Diseases and Pests of Ginger
Ginger is one of the most recognized oriental spices grown for its edible rhizome, which is widely used as a fresh vegetable, spice, and as popular folk medicine. The ginger crop is being affected by insect pests, and non-pathogenic and pathogenic diseases cause production constraints.
Conditions Required for Ginger Farming
- Ginger grows best in sunny and warm climates in a deep but well-draining soil loam that is high in organic matter. The best soil pH value for the growth of ginger is between 6.0 and 6.5 and the plant needs a minimum temperature of 15°C.
- Ginger plants need an average annual rainfall of between 250 and 300 cm for optimal growth and development and need additional irrigation where rainfall is not adequate. Ginger plants will not bear waterlogged soils. Propagation is vegetatively propagated from small sections of the rhizome and called sets. Sets are produced by cutting a small 3 to 6 cm from a living rhizome. Each piece must possess at least one living bud which will produce shoots.
- The ginger sets can be pre-sprouted in nursery seedbeds or pots by covering with a layer of soil or they can be planted directly at the final planting location. The bed must be prepared for planting by digging to the soil to a fine tilth and removing any weeds that are present. The addition of lime to the soil adjusts the pH value while helping to provide the calcium required by the plants in their growth. Lime should be added to the soil in suitable amounts in the fall before planting. The sets should then be planted in early spring at a depth of 5 to 12 cm, leaving 15 to 35 cm between plants and 25 to 30 cm between rows. For optimal growth, the soil temperature at planting must not fall below 25°C.
- Ginger grows in a humid and warm climate. And for effective ginger cultivation, it needs a moderate rainfall at the sowing time till the rhizomes sprout, fairly heavy, and well-distributed showers during the growing period and dry weather for about a month before harvesting. Ginger thrives the best in well-drained soils like sandy or clay loam, lateritic loam, or red loam. A friable loam rich in humus is ideal. The rhizome used for seed must be true to type and free from disease.
- At the time of planting of ginger, apply 25g of powdered neem cake, and mix well with the soil in each pit. Ginger is planted in rows, 25 cm apart at distances of 20 to 25 cm within the row. In the case of the irrigated crop, ridges are made 40 to 45 cm apart and planting is done in shallow pits on top of the ridges at distances of 22 to 30 cm. Bits of seed-rhizomes weighing 20 to 30 g each and having at least one bud are planted at the given spacing.
- Ginger is generally harvested after the leaves senesce, dry out and the stem falls over. Ginger roots are harvested by digging. Ginger is harvested with the help of a cutter bar which is pulled by a tractor. After harvesting of ginger, it should be cured for 3 to 5 days to prevent the development of mildew on the rhizomes.
Major Diseases of Ginger and their Control
Soft rot or rhizome rot
Soft rot is a major disease of ginger. While selecting the area for ginger cultivation care must be taken to see that the area is well-drained as water stagnation predisposes the plants to infection. Choose seed rhizomes from disease-free areas since this disease is seed-borne. Solarization of soil done at the time of bed preparation can decrease the fungus inoculum. Though, if the disease is noticed, the affected clumps are to be detached carefully along with the soil surrounding the rhizome to decrease the spread. Trichoderma may be applied at the time of planting and subsequently if necessary. Limited use of Bordeaux mixture in disease-affected areas may be made to control it as a spot application.
Ginger blast bacterial diseases
It is a devastating disease that generally occurred in production.
Prevention and cure method
(1) Soil disinfection – The use of specific methods are 30 days before sowing, spraying with special tools according to the distance of about 30 cm, the liquid will be applied into the whole good 15 to 25 cm deep soil layer, each point injected 2 to 3 ml, then covered with plastic film for 3 to 5 days, 15 to 20 days after removal of film preparation. Chloropicrin highly toxic should be operated by professional personnel when applying pesticides. Moreover, lime nitrogen can be used for soil treatment.
(2) Agricultural prevention and control. Strict selection of disease-free ginger, rotation of crops, pouring water, fertilizer application net, combined with fine management, control of ginger blast has a significant effect.
Bacterial wilt of Ginger Diseases
Symptoms – Bacterial wilt is the most dangerous disease and the symptoms can be noticed form July to August. The leaf margins of the affected plant turn bronze and curl backward. The whole plants wilt and die. The base of the infected pseudostem and the rhizome produces a foul smell. When the suspected pseudostem is cut and immersed in a glass of clean water, milky exudates will ooze out from the cut end. The typical symptom is the wilting observed in the afternoon in young seedlings.
Management – Seed contamination is the main source of infection. So, procure only healthy rhizome from the disease-free area. Treat the seed with Streptocyclin. Take away the affected clumps and drench the soil with copper oxychloride 0.2%.
Soft rot of Ginger Diseases
Symptoms – Soft rot is a serious seed also soil-borne disease and the symptoms can be seen from July. The yellowing of leaves appears first on the lower leaves and proceeds to upper leaves. Roots arising from the affected rhizome become rotten and show brown discoloration of the rhizome tissue. Sometimes the pseudostem comes off easily with a gentle pull. The rotten parts attract other bacteria, fungi, and insects particularly the rhizome fly. During the rainy season, this disease spreads very fast from an infected field to a healthy field.
Management – Avoid waterlogging. At the time of sowing, treat the rhizome with Bordeaux mixture and again with Trichoderma by 8 to 10gm/liter water. Take away the badly affected plants and drench around the infected plants, later slightly removing of soil with Bordeaux mixture or copper oxychloride by 2g/1 liters of water.
Dry rot of Ginger Diseases
Symptoms – Dry rot is a fungus-nematode complex disease. In contrast to rhizome rot, dry rot appears in a field in small patches and spreads slowly. The affected plants appear stunted and exhibit varying degrees of foliar yellowing. Older leaves dry up first after that younger ones. In the advanced stage the rhizome, when cut open, shows a brownish ring and is mainly limited to the cortical region. The pseudostem of the dry rot affected plants does not come off with a gentle pull in contrast to soft rot. The affected rhizomes are shrunken, dry, and are not marketable.
Management – Soil application of mustard oil cake at the rate of 40 kg/ha before sowing in furrows can check the nematode problem. Hot water treatment followed by seed treatment with the Bordeaux mixture effectively checks the problem. Treating seed with Bordeaux mixture before planting and solarizing the soil can help to decrease the incidence of the disease.
Ginger leaf spot or Phyllosticta blight
Symptom – This disease affects leaves, occurring in the form of spots that are yellow to white, spindle-shaped or long and round, and 2 to 5 cm long. The middle of the spots turns thin and papery. In seriously affected cases, the white spots spread over the whole leaf. Acicular conidiophores can be seen in diseased leaves.
Prevention and Control
- Rotate crops for 2 to 3 years or more.
- Plant in a higher elevated field that is conveniently irrigated and drained.
- Do not supply too much nitrogenous fertilizer, and pay attention to the application of N, P, and K fertilizer in stages in small split doses.
Mosaic viral diseases of Ginger crop
Symptoms – The symptoms appear with dark-green and yellowish mosaic on leaves of ginger in the early stage and stunted of leaves and rhizomes at the late stage of infection.
Protection – Hot-air and hot-water and treatments of affected rhizomes at 45 and 50°C for 3, 6, and 12 h do not alleviate symptoms. The ginger mosaic virus in the standard extract is inactivated in ginger with 10 min exposure at 60°C
Leaf spot diseases in Ginger cultivation
Symptoms – Small spindle to oval spots appear on younger leaves. The spots have white papery centres and dark brown margins enclosed by yellowish halos. The spot later increases in size and coalesce to form larger spots which finally reduces the photosynthetic area. In the case of severe infection, the entire leaves dry up.
Management – Spray Bordeaux mixture (1%) 3 to 4 times at 15 days interval with the initiation of the disease. Good control is achieved by growing the crop under partial shade.
Root-knot nematode diseases in Ginger farming
It is also known as scabies skin disease, the disease is the pathogen of Meloidogyne incognita.
Control method – the root-knot nematode disease pathogens in the soil in a wide range of distribution, long periods of onset, treatment, and prevention are more difficult. Available soil can also use chloropicrin fumigation, nematicidal isopropyl ether 3 kg. If it is found that the growth process of nematodes, available 1.8% abamectin 2000 times Guangen, Meixue irrigation medicine 100 to 150 grams, after irrigation water.
Major Insect Pests of Ginger and their Control
Symptoms – Shoot borer is the main pest infesting ginger. Regular field surveillance and the adoption of phytosanitary measures are essential for pest management. It appears from July to October period. Identify the shoots infested by the borer and cut open the shoot and pull out the caterpillar and finish them. Spray neem oil at fortnightly intervals if found necessary. Light traps will be useful in collecting and attracting the adult moths. An infestation starts in June and continues until October. The moth lay eggs on the growing bud, petiole, or leaf of the young plants.
- Collect all the emerged adult and destroy
- Install light trap during the Middle of May and June, July month for adult mass trapping.
- In the stem borer infested field collection of dead heart and destruction of the same will help in the decrease of the pest.
- Application of Metarhizium.
- Treatment with Beauveria bassiana by 10g/lit water.
Symptoms – Leaf roller is an olive-green caterpillar with a distinct black head that folds the leaves. It folds the leaves and remains inside the fold and defoliates the leaves from the margins and tip. When one portion is complete it moves and makes another fold
Management – Field sanitation must be maintained. Application of Bacillus thuringiensis by 1 to 2 gm /liter of water.
Chinese rose beetle
Symptoms – “Shot-hole” appearance of plant leaves; complete leaf consumed except the leaf veins; the adult insect is a reddish-brown beetle which feeds on plants at night.
Management – Chinese rose beetles are repelled by bright light and attracted to dim light, shining a bright light on plants may help deter them from feeding; covering young plants with e.g. floating row covers can help to protect plants till they are old enough to withstand attacks by the beetle.
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Integrated Pests and Diseases Management for Ginger
- Soil application of Biocontrol agents like T. harzianum and P. fluorescence during planting time by 2-5% gives effective control of the diseases.
- Use good quality rhizome for sowing. Procure disease-free seeds from the disease-free area.
- Before sowing, treat the rhizome in hot water and again in a solution of Bordeaux mixture 1% for 15 min. Add Streptocyclin (20g/ 100 l water) if bacterial wilt is also a problem.
- Treat rhizome with bio-inoculant Pseudomonas fluorescens and Trichoderma harzianum followed by soil application 60 days after planting to reduce rhizome rot. Once the diseases are spotted in the field, take away the affected clumps and drench the soil with Bordeaux mixture 1% at 15 days interval. Diseased plants must be identified while the crop is in the field. Rhizomes from such plants must not be selected for seed purposes.
- Mechanical collection and destruction of grubs, larvae, weevils, and adult beetle periodically will decrease the incidence of insect pests. If white grub is predominant, apply Nimbicidine.
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