Pests and Diseases


Pests and diseases
    Pests
    In India, 34 species of insects are recorded to be pests on black pepper and the important ones among these are listed below.
    Pollu Beetle (Longitarsus nigripennis)
    • This is commonly known as the 'flea beetle'. It is small, shining and brownish-black is colour. The adult beetle lays eggs in small shallow depressions made on the rind of tender pepper berries.
    • The eggs hatch into pale-yellowish grubs which, in turn, bore into and feed on the contents of the tender berries making them hollow. The external indication of infestation is the presence of dark, drying berries possessing a characteristic circular hole in the midst of green healthy berries.
    • A single grub destroys 3 or 4 berries. Fully-fed grubs drop to the soil, construct oval-shaped earthen cocoons and pupate inside them.
    • The total life-cycle of the pest is 40-50 days. It completes 4 generations between July and January.
    • Egg-laying stops by December when the pepper berries mature. The extent of damage caused by the `pollu' beettle goes up to 40% in certain endemic areas.
    • Cultural operations like raking the soil and regulation of shade by standards are reported to be beneficial in reducing 'pollu' beetle infestation. The application of insecticides into the soil can also be effective in controlling pupating grubs.
    • Spraying vines with Endosulfan (0.05%), Quinalphos (0.025%), Dimethoate or Monocrotophos (0.05%) twice a year. during July and September, effectively controls the pest. The leaf extract of Strychnos nux-uomica can be sprayed on the berries as an antifeedent.
    Top-shoot borer (Cydia hemidoxa)
    • The caterpillars of this tiny crimson and yellow coloured moth damage the terminal shoots by boring into them. The intensity of incidence of this pest is more during August to December, when the succulent shoots are available.
    • As the caterpillars bore into the terminal shoot, the growing point is damaged and this results in drying of terminal portions of the vine.
    • The pest takes about a month to complete its life-cycle. Spraying the vines with Endosulfan, Dimethoate, Phosphamidon or Monocrotophos at 0.05% concentration at the point of new shoot emergence has been found to be effective in controlling top-shoot borer infestation.
    • Hexamermis sp. and Aponteles cypris are the bio-control agents, for this pest.
    Leaf gall thrips (Liothrips karnyii)
    • Infestation by leaf gall thrips is more severe at high altitudes and also in nurseries on plains.
    • The feeding activity of the thrips on the leaves causes the leaf margins to curl downwards and inwards resulting in formation of marginal leaf galls.
    • Later the infested leaves become crinkled and malformed.
    • Spraying with Monocrotophos, Dimethoate, Endosulfan (0.05%) or Phosphomidon (0.03%) during the emergence of new flushes reduces the infestation. Montandoniola moraguesi and Androthrips flauipes are the biocontrol agents for this pest.
    Scale insects and mealy bugs
    • Eighteen genera/species of scale insects and mealy bugs, Pseudococcus uigatus, infest black pepper.
    • The scale insects cause severe damage to black pepper at higher altitudes.
    • The Mussel scale (Lepidosaphus piperis) and Coconut scale (Aspidiotus destructor) are important.
    • They are sedentary, remaining permanently fixed to the plant parts and appear as encrustations, mainly on the stems, leaves and berries.
    • They feed on the plant sap, cause yellowing and wilting of infested parts.
    • In severe cases of infestation the affected portions of the vines dry up.
    • The infestation is more severe during summer. Spraying with Monocrotophos or Dimethoate (0.1%) or Quinalphos (0.05%) during January-February at 15 day intervals checks the infestation. A total of
    • 17 predators and 4 parasitoids of the scale insects have been recorded, of which Chlocarpus sp., Encarsia lounsburyi and Pseudoscyrnnus could be employed for the biocontrol of scale insects.
    Nematodes
    • Plant parasitic nematodes viz., Radopholus similis (burrowing nematode) and Meloidogyne incognita (root-knot-nematode), cause considerable damage to pepper plantations. The initial symptom is the turning of a few leaves from normal green to yellow. With the gradual advancement of the disease, many leaves turn yellow followed by defoliation and die-back, resulting in loss of vigour and leading to the death of the vine.
    • The nursery mixture should be sterilised with Methyl bromide to denematise the soil. In the main field the pits are treated with nematicide (Phorate 10 G or Carbofuran 3 G) at the time of planting. The planting of nematode-free, healthy rooted cuttings is essential. Phorate 10 G or Carbofuran 3 G @ 3 g a.i. per vine is applied once in May-June and again in September-October to check the population of nematodes. The variety CLT-P-812 is resistant to the root-knot nematode.
    • There are a few species of mealy bugs which infest the leaves, stems and sometimes the spikes and berries. Spraying Dimethoate, Parathion-methyl and Quinalphos (0.1%) is an effective control measure.
    • Pterolophia griseovaria and larva of Synegia sp. which feed on the spikes and foliage, are the new pests recorded on black pepper.
    Diseases
    In India, although 17 diseases affect black pepper, the following are serious ones.
    Quick wilt or foot-rot disease (Phytophthora palmivora Var. piperis)
    This is the most serious and dreaded disease affecting the pepper vine. Three types of symptoms, i.e., leaf-rot, collar-rot and root-rot, are generally observed in a quick wilt infected plant. The first visible symptom on the leaf is water-soaked lesions in the infected area.
    Within 2 days the water-soaked areas change colour and develop into necrotic spots surrounded by a yellow halo. The lesions expand rapidly and cover large areas of the leaf. Subsequently, the infected region shows a wet rotting and causes defoliation.
    Collar-rot is the most fatal type of infestion in pepper. It appears on vines at the ground level and above, up to about one metre height.
    The initial symptom is the appearance of water-soaked lesions similar to those on the leaves. On the stem and branches, lesions the spread and the affected area gets rotten within 8-15 days. In the advanced stages, the affected tissues emit a foul smell. Infection of the collar region progresses towards the underground portions of the stem and also to the root system and causes their rotting as well.
    In the case of root-rot, the degree of damage depends upon the type and the number of roots infected and the extent of rotting. The infection generally starts on the fine roots and progresses towards the main roots, reaching finally underground portions of the stem. By this time, the entire plant collapses.
    The disease can be effectively controlled by the following practices.
    • Before the onset of the monsoon, good sanitation measures should be taken in pepper gardens by removing all dried vines and leaves.
    • Good drainage should be provided.
    • After a few early showers from the Southwest monsoon, the soil should be drenched twice around the base of the vine at a radius of 30 to 45 cm with 0.1% solution of methoxy ethyl mercuric chloride (Agallol G 3%) or Copper oxychloride (0.2%).
    • The vines should be sprayed and drenched with 1% Bordeaux mixture during the onset of the Southwest monsoon and once again during the peak period of monsoon.
    • The main stem should be pasted up to 1 to 1/2 m above soil level with Bordeaux paste (10% Boreaux mixture) during the onset of the monsoon will protect the stems from infection.
    • Metalaxyl 500 ppm, a systematic fungicide, potent upto 50 days, can effectively be used to check Phytophthora infection.
    • Application (per vine) of neem cake (1 kg) + Trichoderma harzianum (50 g), Ridomil MZ (metalaxyl) + garlic and mustard seed extract (2 kg garlic + 1/2 kg mustard, crushed and volume made upto 200 lit) + mulching the wet soil with transparent polythene sheets during the hot summer is the most effective treatment. The biological control measure should be followed by spraying of Akomin 6.2% (Potassium phosphate) in August or 0.3% Potassium phosphate 31/vine and drenching@51/vine twice, before the onset of the monsoon and during the second week of August.
    • Prior inoculation with VAM provides better protection for the root system against this disease.
    • The sources of resistance/tolerance for this disease are the P-24 and P-603 varieties and Piper colubrinum and P arboreurn
    Slow wilt
    This is a complex problem involving fungi, nematode, soil and nutritional factors. The fungal pathogens associated with this disease are Fusarium, Colletotrichum, Rhizoctonia bataticda, Diploida, etc. The slow-wilt disease of pepper as the name suggests is identified by gradual appearance of wilting symptoms in the pepper vines. The symptoms usually appear after the Northeast monsoon. The leaves and tender shoots first lose their turgidity and become flaccid, as if the plant suffers from moisture deficit in the soil. Later as the disease progresses, the leaves become pale and then yellow due to infestation by the nematodes Meloidogyne incognita and Rhodopholus similies and finally they shed. The symptoms become more pronounced during summer. With the onset of rains, new flushes are produced and the wilting symptoms apparently disappear. But after the Northeast monsoon, or the following season, the symptoms reappear more severely. The process is repeated for one or two years. The root system of the affected plants withers and decays. After the first appearance of the disease, it takes two to three years for the death of the plant, during which period, the health, vigour and yield of the plants gradually reduce.
    The following control measures have been suggested to protect possible invasion of the organisms.
    • A soil drenching treatment should be given with 0.1% mercurial fungicide or 1% Bordeaux mixture @ 5-10 1/vine 2-3 times during the monsoon season to the root zone.
    • Apply Phorate 10 G or Carbofuran 3 G @ 30 g/vine plus Bordeaux mixture spraying and drenching plus soil application of neem cake @ 2 kg/vine during May-June and October- November.
    Pollu disease (Anthracnose)
    • This is a berry disease caused by Collectotrichum gloeosporeoides.
    • The disease can be controlled by two rounds of spraying with 1% Bordeaux mixture or Captafol (1.0%) once before flowering and at berry formation stage or spraying 0.2%
    • Carbendazim before the onset of monsoon and subsequently at monthly intervals till September.
    Stunting disease
    This disease is caused by the cucumber mosaic virus (CMV).
    The symptoms are:
    (i) stunting, crinkling, cupping and narrowing of leaves,
    (ii) scattered chlorosis flecks on the leaves,
    (iii) chloratic flecks along veins, leading to interveinal chlorosis,
    (iv) vein banding, severe interveinal chlorosis with dark green veins,
    (v) leathering of leaves with mosaic pattern and vein banding. No effective measure has been recorded against this disease.
    Phyllody, caused by phytoplasmas and leaf-spot diseases, is also of increasing importance in black pepper. Yellow disease is reported to be a serious disease of black pepper in Indonesia.

Last modified: Friday, 9 March 2012, 11:29 AM