Termite Galleries

RICE (PADDY)

TERMITE MANGEMENT IN RICE

In India, termites are recognised as of regional importance in upland rainfed rice and also irrigated wheat-rice system (DPPQR&S, 2001). In India 6.5 m ha area is under rain fed upland rice, out of which 5.2 m ha is in Eastern India (Maiti et al., 2007). Termites (Odontotermes obesus and Microtermes obesi) are the most important species in red-light textured soil with low water holding capacity under prolonged drought conditions. By an analysis of ecology-wise key pests of rice in India (www.rkmp.co.in), it is revealed that rain fed upland rice comprised 6 mha area (with a meagre yield of 1.3 t/ha).

Major insect pests are stem borers, gundhi bug, mealy bug, termites and root aphids. Although, termites are typical problem in upland rice, infestations can also be there in light-textured low moisture content soils in rainfed wetland areas as well. Broad-spectrum and organochlorine insecticides have been largely relied upon for the control of termites (Mahapatro, 2011; Mahapatro et al., 2011).

The limitations associated with the application and efficacy of these chemicals such as the destruction of non-target insects, high cost of the chemical insecticides, accidental poisoning and environmental pollution emphasizes the need for alternative methods. Other non-chemical control measures such as biological control, cultural control, use of plant extracts and host plant resistance are being relied upon to control termite infestation. Because of the unique advantages of host plant resistance, it is believed to be a durable strategy in pest management in developing countries. Unfortunately practically no work has been done in this regard in India.

No doubt, termites are one major biotic stress in upland rice. In dealing with termites in rice, the following headings are detailed for a common understanding.An integrated approach of all feasible frontier technologies and indigenous knowledge in termite management is attempted in this pursuit.

Pest status in rice

Termites are polyphagous, and infest a wide range of host plants. Usually termites infest upland paddy but it also attack in lowland where there is no assured irrigation/ water stagnation. Termite colony attacks on germinating seed or growing root causing complete drying of crop. The damaged plant can easily be pulled out by hand. Even though they arepermanent residents ofnon-flooded environment,termites may attack rice but can readily be controlled withinsecticides.

ermites attack living rice plants when dead plant material is not available and generally late in the crop growth stage. They attack drought-stressed crops and prefer older plants having greater cellulose content. They tunnel through the plant stem and eat the roots. The attacked plants become stunted and then wilt. Termite attack also predisposes plants to further damage by ground-dwelling pests such as rodents, ants, saprophytic fungi and bacteria. Yield losses due to termite damage ranging from 50 to 100% have been reported (UNEP, 2000).

Termites in paddy can also occur in light-textured soils in rainfed wetland areas. Infestations are severe on light textured soils with low moisture content. Some grassland termites make nests composed of many tunnels deep in the soil. They attack living rice plants only when dead plant material is not available. They attack a drought-stressed crop, but prefer older plants having greater cellulose content. They tunnel through plant stems and eat roots. The plants become stunted and then wilt. Damaged plants can easily be pulled by hand.

Termites are more serious in Latin America and Africa than in Asia. The common Asian species that attack rice plants are Macrotermes gilvus, Heterotermes philippinensis, and Coptotermes formusanus. In Africa, Microtermes and Macrotermes termites have been reported as pests of rainfed upland rice (Pathak and Khan, 1994). In India, termite species recorded in rice are Odontotermes and Microtermes spp.

In wheat-rice irrigated agro-ecosystem particularly in northern India, termites can be a problem. Actually termites are of serious concern in wheat. However, careful handling with water management can be helpful in tackling the termites. Soil treatment, seed treatment and spot applications are taken on need-basis.

Causes of termite outbreaks

Presence of termite nests/mounds around the paddy field or farm.
Warm and dry climatic conditions (i.e. lack of rainfall) – uneven rainfall due to climate change.
Introduction of exotic crop species. Indigenous crop species capable of coping with termite infestation as they have evolved some level of resistance
Presence of unhealthy crop species that have been subjected to biotic and abiotic stresses such as drought, weeds, diseases, etc.
Lack of effective termite control measures and lack of suitable integration of termite control tactics.

Some grassland termitesmake permanent nests composed of many tunnels deep in the soil. Other species make nests asmounds above the ground.The tunnels are lined with body waste to seal the wallsso that high humidity can bemaintained.

Damage

Most grassland termites lack symbiotic protozoa to digest cellulose. Instead they culture fungi in underground fungal combs. Fungal gardens (=combs) are made by termite workersof partly digested plantmaterial. This plant materialbecomes inoculated with the fungi and the termites latereat the combs. Workers constantly construct and eat the fungal combs in theirnests.

Termites prefer dead to living plants but when their preferred food is gone, they feed on living roots. Afterland preparation, the termite workers feed on living plants.They tunnel through plantstems and eat roots, causingthe plants to become stunted. Damaged plantscan easily be pulled by hand.When rice is notvigorously growing, drought encourages termites to attacka standing crop.

Management Aspects

Cutural control

Termite mounds in and near the paddy field to be located and exterminated by manual digging and dequeening.
To takeadvantage of termites perference for dead plant material, farmers can divert the pest from the growingcrop by putting crop residuein the field at planting.
Deep ploughing with chisel plough is helpful in reducing termite infestation.
Populations of soil-dwelling pests of dry land rice (such as white grubs, mole crickets, termites, ants, and root bugs) can be reduced by increasing the number of tillage operations.

Chemical control

Decision on insecticide use should be based on the history of damage in a particular field or perhaps even on portions of a field.
Treating the seeds with insecticide at planting is usually effective against termites.
If higher dosages are required,granules are applied in the seed furrows or hills

In termite and nematode prone areas, incorporate carbofuran (Furadon®) @ 2.5 kg ai/ha into planting row. To ensure uniform application insecticides can be mixed with sand (ratio, 1: 4)(DPPQR&S 2001).
In water scarce area chlorpyriphos 20EC can be admixed with sand/soil @ 3-5 litres (depending upon the termite infestation), and then can be applied in the field.
In standing crop sand mixed with chlorpyriphos can be applied in the seed furrows or rice hills.
Fipronil granules (0.3%G) can be applied to soil, after which a light irrigation is required, however in rain fed situation this can be done based on the weather forecast. Please note that fipronil is not having label claim for application in rice crop for termites.However, label claim is there for stem borers (with recommendation of 16.67 – 25 kg/ha formulated product (0.3% Granules, waiting period 32-days)(http://cibrc.nic.in). In hilly tracks (near water bodies also) fipronil is better be avoided.
Never use chlorpyriphos with irrigation water, when irrigation facility is there. It is a crude way and not eco-friendly approach.
Proper care should be taken while handling chemicals. Use shoes, apron, gloves – all protective clothing etc.

Management options in Assam are as follows (AAU)

Locate the termitorium and destroy by pouring chlorpyriphos solution into termitorium.
Seed treatment with chlorpyriphos 0.5‐ 1 kg/ 100 kg seed (?).
Seedling dip with chlorpyriphos.
Flooding/water stagnation avoids termite infestation.
Application of chlorpyriphos 10 G granules @ 7.5 kg/ ha.

Termite control non-chemical methods:

To control termite in the field some farmers cut approximately 5 kg each of Calotropis and Kheemp (Leptadenia pyrotechnica) twigs into small pieces and put them in anearthen pot. Then add 1 kg salt and 10 L water/cow/human urine. The pot is kept in a pit for 15-20 days. The suspension is filtered through cotton cloth and filtrate is applied as an insecticide @ 10 L/ha in irrigation channel (Source: IntegratedDisease Pest Management in Sri Paddy. SRI Secretariat (SDTT), Bhubaneswar, 24p.).
Biopesticides such as neem seed oil (22Lof neem seed oil concentrate in 220L of water/ha) and neem powder (800 kg/ha) may be used.
The entomopathogenic fungus Metarrhizium anisopliae is an effective biological control strategy (2 grams spore powder of Metrrahizium mixed with 60 cm³ of wood powder/saw dust. Put mixture in a hole of 3 cm depth and cover with a small quantity of saw dust to protect spores against sunlight).
Application of red palm oil mixed with pawpaw (=papaya) is an indigenous biological control practice. The mixture attracts soldier ants that attack and drive away the termites.
Use of resistant/tolerant rice varieties such as LAC 23, NERICA1, 2, 5, 14 and others (for African nations)(# 2-5: source: www.rkmp.co.in).
Extracts of juice of immature papaya fruits controls termites (CTDT, 2008).

Elimination of the termite mound

Mounds are permanent abodes of termite where they multiply and become a continuous source of termite attack. Thus, it becomes necessary to destroy these termite mounds as a first step to check the termite attack. The generally accepted chemical method of termite control over the years has been liquid insecticides. However chemicals can be expensive and have manyharmful effects to environment.One should know which mound is active and needs control. After the rainfall in its season, the fresh mound growth can well be marked on the mounds.Quick and complete extermination of the mound-colony at low cost can be achieved by treating the mounds by pouring in, through a funnel, water suspension of insecticides, through two or three holes in the mound. The minimum rate is 9 litre of liquid per 10 cu. ft. (2.8 cu.m) of mound volume. For sub-cylindrical mounds, as in O.obesusfollowing height-liquid ratio may is maintained:

Height of mound	Dosage of liquid insecticide
*1 - 2 foot 3 foot	2 - 4 litres 4 - 5 litre
4 foot	20 - 25 litre
5 foot	45 - 50 litre
6 foot	80 - 85 litre

*Normally these are new colony growths which can be dug out easily.

Chlorpyriphos 20%EC (2-3 ml/L water) and imidacloprid 17.8%SL (1 ml/L water) is the liquid solution to be poured into the mounds (Mahapatro, 2013).

We can control the termitarium without use of harmful liquid chemicals:

(a)The regular disturbance through cracking prevents termites from building extensive mounds. Manual and explosive destruction ofnests followed by the removal of the queen is also effective.

(b) Manual digging, collecting queen(s) and killing.

Research gaps

Seed treatment of rice may be a viable option in termite management in an ecofriendly way. However, concerted research efforts are to directied in this line. Persual of literature reveals that the seed treatment for rice recommendations varies widely. Total Seed Treatment Campaign of Govt of India recommends chlorpyriphos 3 ml/kg rice seed, and another paper from CRRI (Cuttack) i.e., Rath and Dani (2009) cited need based protection(seed treatment with chlorpyriphos 20EC @ 3.75 lit per 100kg seed. The last mentioned seed treatment dosage for chlorpyriphos works out to be 37.5 ml/kg rice seed. This seems too high, and toxic to seeds. Field trials must be done only after conducting laboratory tests for toxicity (germination test) following standard protocols.

Climate change and termites

Pests have been associated with crops since times immemorial. Butunder changing environment their number has increased and the minorpests now become the major one causing greater damage to the crop. Thisis evident from the fact that rice crop had 3 major pests in 1965 which hasincreased to more than 15 in 2005. The greater incidence of disease pestleads to greater chemical application resulting in higher input cost and agro-ecological imbalance.

Causal relationship exists between climatic conditions and the swarming and colony founding behaviour in termite species. Swarming is meant for the purpose of dispersal and the colony founding. This results in the perpetuation of the species. It seems probable then that the flights must be scheduled in response to some common signal in the environment, such as change in temperature, atmospheric pressure or light intensity. However it would not be surprising to find that certain temperature and moistureconditions are prerequisite for the operation of these cues. Sangamma and Chimkod (2012) concluded that the main stimulus factor for the swarming cues in the termite species (Odontotermes wallonensis and O. brunneus) depends upon the pre-monsoon rains, temperature and humidity of the climatic conditions.

Climate change that brings uneven rainfall pattern greatly influences the termite infestation in upland rice. As mostly short duration varieties are used in upland, shifts in rainfall or monsoon drastically changes the coincidence of termite peak infestation period with the crop phenology. Location specific researches are needed to verify these facts in rice.

Points to ponder

Effective traditional practices against termites include: smoking the termite nest, use of salt, and flooding of termite nests with water.
Biopesticides such as neem oil, neem powder and powdered tobacco are effective against termites because they serve as potential replacement for persistent chemical pesticides, such as endosulfan/carbofuran which has already been banned in several nations.
Entomopathogenic fungus Metarrhizium anisopliaeis an effective biological control strategy against termite attack on upland rice. Commercial formulation (1.15%WP, 2.5 kg/ha in 500L water, label claim for BPH) is available in the market, that may be tried in the field for validation (http://cibrc.nic.in/mup.htm).
The application of red palm oil mixed with papaya is an indigenous biological control practice. The mixture attracts soldier ants that attack and drive away the termites.
Research needs for seed treatment must be given due importance.

Bibliography

AAU (Assam) Integrated Pest Management in Paddy, SMS (Entomology), Krishi Vigyan Kendra, Dhemaji, Silapathar, Assam Agricultural University.
CTDT (Community Technology Development Trust)2008.Integrated Pest ManagementCost-saving Techniques for Smallholder Farmers.CTDT,286 Northway Road Tel: +263 4 576 091/589 242, Harare - Zimbabwe (www.ctdt.co.zw34p.)
DPPQR&S (Directorate of Plant Protection, Quarantine & Storage) 2001.IPM Package for Rice, Government of India, Ministry of Agriculture, Faridabad-121001, 35p.
Integrated Disease Pest Management in SRI Paddy. SRI Secretariat (SDTT), Bhubaneswar, 24p.
Mahapatro GK 2011. Environmentally sustainable termite control: an Indian perspective. Recent Trends in the Integrated Pest management. Invited papers of the 3^rd Congress on Insect Science, April 18-20, 2011, INSAIS, PAU, Ludhiana, India.
Mahapatro GK 2013 Termite mounds and their elimination (Hindi), PrasarDoot, 17 (1): 48-49 (February issue 2013).
Mahapatro GK, Ganesh Rai and Sachin Kumar 2011.Termites in agriculture and their control(In Hindi),PrasarDoot, 15 (2): 35-39 (December issue 2011).
Maiti D, Shukla VD, Mehdi MM and Rath PC 2007.Validation of IPM strategy for rainfed upland rice (OryzasativaL.) under medium rainfall plateau of Eastern India through on-farm trials.Oryza, 44 (2): 140-144.
Oikeh SO, Nwilene FE, Agunbiade TA, Oladimeji O, Ajayi O,Semon M, Tsunematsu H and H Samejima(www.warda.org). Growing Upland Rice: A Production Handbook.Africa Rice Center (WARDA), Cotonou, Benin, 40p.
Pathak MD and Khan ZR 1994.Insect pests of Rice.IRRI and ICIPE.89p.
Rath PC and Dani RC 2009. Pest management strategy for rain-fed upland rice in coastal Orissa, Oryza, 46(3): 231-233.
Roonwal ML1979.Termite Life and Termite Control in Tropical South Asia, pp xii+177. Scientific Publisher, Jodhpur.
SangammaItagi and Chimkod VB 2012. Swarming behavior of the termites, Odontotermes brunneus and Odontotermes wallonensis. World Journal of Science and Technology, 2(12): 1-4. (www.worldjournalofscience.com)
Stevens, Mark M; Reinke, Russell F; Coombes, Neil E; Helliwell, Stuart; Mo, Jianhua 2008. Influence of imidacloprid seed treatments on rice germination and early seedling growth, Pest Management Science, 64 (3): 215-222.
UNEP (United Nations Environment Programme) 2000.UNEP/FAO/Global IPM Facility Expert Group on Termite Biology and Management. 47p.
WH Reissig, EA Heinrishs, JA Litsinger, K Moody, L Fiedler, TW Mew, and AT Barrion 1986.Illustrated Guide to Insect Pest Management in Rice in Tropical Asia, International Rice Research Institute, Los Banos, Laguna, Manila, Philippines, 409p.
www.rkmp.co.in -Krishnaiah K and Varma NRG.Changing Insect Pest Scenario in the Rice Ecosystem – A National Perspective, Rice Knowledge Management Portal (RKMP), Directorate of Rice Research, Rajendranagar, Hyderabad 500030. 28p.

NB:

This is a part of a paper lectured by National Fellow, in 21-days Summer School Programme, Title: New horizons in biotic stress management in rice under changing climate scenario, Central Rice Research Institute (CRRI, now NRRI), Cuttack, Odisha (16-09-2013).

Part of it also published in Curr. Biotica, 8(1): 97-108.