Integrated Pests and Diseases Management
Capsicum being relatively long duration (9-10 months) crop in polyhouse, the plant parts (vegetative, floral & fruit) are the more exposed to an adverse effect on the yield, quality and market value of the produce. Hence their identification and management at the right stage of the crop should be given importance. The major pests and diseases, their symptoms and their management in capsicum are given below. The major focus has been given on adoption of an integrated approach to managing pests and diseases, which help to reduce the pesticide load, cost of chemicals and avoids the resurgence of pests and diseases.
Insect pests of Capsicum and control
Thrips cause upward curling of leaves, sucks sap and reduce leaf growth, plant growth, yield and market value of produce. It also reduces leaf area and hinders absorption of nutrients and water by the plants. Increased infestation leads to blackening and drying of leaves and irregular fruit bearing.
Remove affected plant parts including leaves, flowers, and fruits. Keep the plots clean by removing all the dropped plant parts. Spray Pongamia oil (5-8 ml/L) or Neem seeds kernel extract (NSKE 4%) or Pongamia / Neem soap developed by IIHR (7gm/L) or fipronil (1ml/L) or chloropyriphos (2 ml/L) or acephate (1.5g/L) or Imidacloprid (0.5ml/L). Drenching of soil using chloropyriphos (4ml/L) or imidacloprid (0.5ml/L).+
Young larvae and adults feed on leaves, bud, and fruits, suck sap from plant parts which in turn causes downward curling of leaves. The size of leaf, fruit, and plants gets reduced, fruit and flower drop affecting the market value of the produce. This pest infestation increases with increased temperature coupled with high humidity.
Remove the pest damaged plant parts including leaves, flowers and fruits and spray Pongamia oil (5-8 ml/L) or Pongamia / Neem soap (8-10 g/L) or dicofol (2ml/L) or wettable sulphur (2ml/L) or abamectin (0.5ml/Ll) or eco mite or propargite or chlorophenapyr (1ml/ L) or fenazaquin (1 ml/L).
Nymphs and adult aphids suck sap from leaf veins and younger leaves resulting in reduced plant growth and a decrease in yield. Its infestation not only causes curling of leaves but also spreads viral diseases.
Keep a close watch on the plants at regular intervals for aphids’ infestation. Spray Pongamia / Neem soap (8-10 g/L) or imidacloprid (0.5ml/L) or thiomethoxam (0.5g/L) or dimethoate (2ml/L).
4. Fruit borer
Fruit borers are very active during the night. The adults lay eggs on fruits, flowers, and leaves in large number and the nymphs that come out of eggs, feed on fruits and leaves causing the heavy destruction of crops and severely affects the quality of the produce. Whenever night temperature is low, coupled with cool and high humidity the infestation is increased. Since eggs are laid in the group, the larva also feeds gregariously on leaves at one place, which can be easily identified and destroyed.
Pick and destroy nymphs and adult insects. Eggs are laid and hatch in groups, which is easy to identify from a distance. Hence they should be identified and destroyed immediately. Spray thiodicarb (1ml/L) or carbaryl (3g/L) or indoxcarb (1ml/L) or rynaxypyr (0.5ml/L) or chlorofenfur (1.5ml/L) or fipronil (1ml/L). In addition to the sprays, grownup adults should be subjected to methomyl baiting*, which is a safe, healthy and effective practice.
* Methomyl baiting procedure:
Prepare a mixture of 10 kg paddy husk and 1 kg jaggery solution and store for 6-8 hrs. Add ½ kg methomyl to the mixture. Small sized balls of the mixture are made which are spread near the root zone of the plants and also around poly house/ net house to avoid infestation of fruit borer. It should be applied during night hours, and the domestic or pet animals should not be allowed to move in and around net/ polyhouse over night.
Nematodes are commonly seen in solanaceous crops when grown 3-4 times continuously in the same field. Initially yellowing of leaves can be observed followed by a reduction in leaf size, count and a drastic reduction in the size of fruits. When the infected plant is uprooted and observed, small and big nodes filled with a large number of nematodes nodules can be observed on roots depending on the level of infestation.
Go for crop rotation with non-solanaceous crops like marigold, sweet corn, and cabbage to avoid nematode. Bio-pesticides enriched Neem cake (as explained earlier) is to be applied @ 800 kg/ acre 4-5 days before transplanting to the beds. Apply carbofuran (furadan) granules @ 20kg /acre at the time of planting. Keep a close watch on nematode infestation of the plants, particularly in 2nd and 3rd crop. The insecticides should always be mixed with spreader or sticker while spraying. The plants from top to bottom should come in contact with spray for better result and care should be taken to compulsorily cover the entire body with full clothes, mask, gloves, and aprons while spraying.
Capsicum diseases and control
1. Damping off
Infection takes place at the base of the young seedlings just above the ground level which leads to wilting and later death of seedlings. Any damage caused to seedlings while transplanting can also lead to damping off or seedling wilt besides fresh infection in main field or infection that is carried from the nursery.
Drench carbendazim (1g/L) or metalaxyl MZ (2g/L) or copper oxychloride (3g/L) or captan (3g/L) drenched to the base of the plant at about 25-50 ml/plant
2. Powdery mildew
The disease initially appears as tiny yellow spots on the surface of leaf and powder like material on the lower surface leading to a powdery growth covering the entire lower surface of the leaf which leads to drying and dropping of leaves at later stages. The disease reduces the growth of leaves and fruits leading to low quality and quantity of the produce.
Spray Pongamia /Neem oil (7ml/L) + sulphur WDG-80 (2g/L) or wettable sulphur (2g/L) or hexaconazole (0.5ml/L) or myclobutanil (1g/L) or dinocap (1 ml/L) or azoxystrobin (0.5ml/L) or penconazole (0.5ml/L) or flusilazole (0.5ml/L).
3. Cercospora leaf spot
Cercospora appears initially as tiny yellow spot on leaf surface leading to increased dark grey spots which spread on entire leaf resulting in dropping of the leaf.
Spray chlorothalonil (2.5g/L) or mancozeb (2.5g/L) or carbendazim (1g/L)
This disease appears during fruiting and flowering stage resulting in tiny oil like spots on leaf surface resulting in rottening and blackening of plants. Later plant weakens and dies in 2-3 days. Heavy and continuous rainfalls coupled with high humidity favour disease appearance and its quick spread. Phythopthera disease is relatively more severe in net houses which may lead to 40-80 per cent crop damage.
Spray copper hydroxy chloride (3g/L) or bordeaux mixture (1%) or metalaxyl MZ (2g/L) or dimethomorph + mancozeb (1g + 2.5g/L) or fosetyl aluminium (2g/L) or azoxystrobin (0.5ml/L).
Severely infected plant parts should be destroyed. It is better to avoid capsicum cultivation in severely affected net-houses.
5. Viral diseases
Viral diseases are transmitted through aphids and thrips leading to upward and downward curling of leaves with a yellow spot in the middle of the leaf and sometimes on fruit also. Heavy infestation leads to dropping up of leaves, stunted plant growth and reduces quality and quantity of fruits. Virus affected fruits are unmarketable.
Grow nursery beds under nylon cover (50 mesh), proper management of aphids, mites and thrips which acts as disease transmitting vectors and disposal of diseased/infected plants, control infestations of viral diseases.
Steps to be followed during use of pesticides and insecticides
- Pesticide residues in produce sent for marketing should not cross the safety level (MRL) of the respective pesticides.
- Always cover your body with protective wares viz., masks, gloves, and apron while spraying the chemicals to avoid health hazards.
- Go for crop rotation (in net/polyhouse after continuous growing of the same crop) with field/ pole beans, marigold, cabbage, cauliflower, sweet corn and also with any other profitable crop including sweet/European cucumber or green peas as per market value.
- The doors of polyhouse/ net house should always be kept closed to protect from pests, diseases and foreign materials.
- A minimum number of entry or exit of the essential working staff and others only need to be entertained.
In poly house cultivation of capsicum, high plant density, mono cropping of susceptible genotypes and increased labour activities make plants more prone to pests and diseases like mites, thrips, whiteflies, powdery mildew, and nematodes. Thus, chemical control of pests become necessary and often several sprays of insecticides/fungicides are given even at near harvest stages of the crop. In a polyhouse, the volatilization and wind drift losses of pesticides are lesser which may result in higher initial deposits of pesticide residues on the plant and soil, while degradation of pesticide residues may be higher due to higher average temperatures.
Also, a polyhouse reflects back 43% of the net solar radiation incident upon it allowing the transmittance of the “photosynthetically active solar radiation” in the range of 400-700 Nm wave length. Thus there will be lesser UV radiation incident upon the crop in a greenhouse than in the open field in the same area, especially if a shade net is also used.
Since most pesticides are UV-degradable, there is the likelihood that pesticides will persist for a longer time. It is thus important to evaluate the persistence of pesticide residues in these crops under polyhouse conditions so that safe waiting period for important pesticides used in polyhouse cultivation may be established. There is no information in this area at the national level, and very little information is available even at international level. IIHR, Bengaluru has established that pesticides tend to persist for a longer time in crops grown in polyhouse when compared to crops grown in open field in the same season.
Thus, it is important that waiting period of pesticides be established specifically for capsicum grown under polyhouse conditions and accordingly use of pesticides may be recommended for chemical control of pests in this crop and to make the produce safe for human consumption at harvest. Given below is a list of the safe waiting period of some pesticides that have been worked out for capsicum grown in the poly house.
|Insecticide||Target Pest||Safe waiting||MRL(EU)|
However, there are a lot of other insecticides viz. thiamethoxam, rynaxypyr, indoxacarb, eco mite, dicofol, fipronil, propargite, etc. and fungicides viz. mancozeb, metalaxyl, hexaconazole, dimethomorph, carbendazim, difenaconazole, azoxystrobin which are used in this crop or are recommended for use.
Currently, no data exist anywhere, even in literature, on residue persistence and waiting period for these pesticides in polyhouse grown capsicum. Since poly house cultivation of capsicum is gaining importance, there is an urgent need to generate residue dissipation data for these pesticides, and thereby establish safe waiting periods required for harvest. At IIHR, Bengaluru work has been initiated to determine the persistence pattern of pesticides and their waiting periods in polyhouse grew vegetables, especially, capsicum and tomato. Accordingly, the persistence of residues of acephate, iprodione, chlorothalonil, abamectin, etc. have been determined under polyhouse conditions.
Harvesting and yield
Early morning hours are best suited for capsicum harvest. Green capsicum can be harvested at 55 to 60 days after transplanting, yellow capsicum at 70-75 days whereas red capsicum at 80-90 days. Fruits can be harvested once in 3 to 4 days. Yellow and red fruits can be harvested when they have gained 50-80 per cent of the colour development. After harvest fruits should be kept in cool place and avoid direct exposure to sunlight. The fruits should be handled carefully by adopting clip harvest technique and scuffing should be minimized. The average yield of capsicum per acre is 30-40 tons.
Post Harvest Management
Grading Capsicums are highly perishable and lose water very rapidly due to shriveling, drying & softening of the fruit which a c c e l e r a t e s deterioration. Good quality fruits are selected and are cleaned with a clean, dry and soft cloth to remove water drops or wetness or powdery residues of pesticides/ fungicides, if any, found on the fruits. Good quality fruits with 2-3 lobes weighing < 150 gram are graded as B grade fruits.
Good quality fruits with uniform maturity, color, shape, size and free from defects spots, bruises or decay and pesticide residues should be used for packing while fruits showing signs of sunscald, mechanical or insect damage, or diseased misshaped and damaged fruits should be discarded. Fruits with 3-4 lobes weighing 150 gram and more are grouped as A grade fruits Only the graded fruits are packed in the carton boxes
“Protected Cultivation Of Capsicum — Vikaspedia.” Vikaspedia. N.p., n.d. Web. 28 Aug. 2017 <http://vikaspedia.in/agriculture/crop-production/package-of-practices/vegetables>.
Protected Cultivation Of Capsicum — Vikaspedia. (n.d.). Retrieved from http://vikaspedia.in/agriculture/crop-production/package-of-practices/vegetables
- Indian Institute of Horticulture Research