Rice Root-Knot Nematode (Meloidogyne graminicola): A Major Menace in Rice Production

Abstract

Rice is an important major staple food crop of the world which is affected by various biotic and abiotic stresses. Among biotic stresses, plant parasitic nematodes are considered as major constraints. However, of late, Meloidogyne graminicola has emerged as pest of International importance and it is considered as number one enemy of rice crop. Being a soil borne and hidden organism in rice causes a yield loss up to 80%. Due to its adaptation, distribution, broad host range and ability to survive under different abiotic factors especially physical and chemical properties of soil, such as soil pH, organic carbon, EC, nutrition, temperature, soil type, moisture, etc., The management is a challenging issue due to non-availability of nematicides and also effective management practices all these factors represents, Meloidogyne graminicola a serious menace for rice production. Considering the impact of this nematode in rice production a literature is mainly focusing on distribution, symptoms, biology, survival strategies and management practices.

1. Introduction

Rice (Oryza sativa L.) is the important staple food for more than half of the world’s population [1] and depends on rice for more than 20% of their daily calorie intake [2]. More than 90% of the world’s rice area is in Asia, which is the home for more than half of the world’s poor, and more than half of the world’s rice cultivators [3]. Rice is affected by various biotic and abiotic stresses, among biotic stresses the diseases caused by fungi, bacteria, virus and nematodes are considered as major threat. They affect the increasing productivity of rice. Among various diseases, blast, bacterial blight, sheath blight, sheath rot, brown leaf spot, false smut, rice tungro virus and rice root-knot nematode are economically important and cause significant yield loss [4]. Recently, rice root-knot nematode (Meloidogyne graminicola) as becoming serious threat in both upland and low land rice [5].

Root-knot nematode (Meloidogyne spp.) is biotrophic, sedentary endoparasite and perfect examples of highly adapted and evolved root parasitism. They are one of the major menace in the production of field and horticultural crops throughout globe. Meloidogyne sp. create permanent feeding sites to enjoy continuous supply of nutrient and water from the infected host and continuous feeding results in the production of galls or knots [6]. The resultant infection in host is due to the hypertrophy of vascular tissues and hyperplasia of root cortex cells [7]. Besides the galls on roots, an infected plant also exhibit poor growth, stunted growth, reduced tillers, unthriftiness and general wilt symptoms the damage is aggravated by the parasites interaction with other pathogens such as fungi and bacteria [8]. In the present era of advanced farming system, rice is prone to attack by various of abiotic and biotic stresses which results in reduce the crop yield, which includes tiny hidden organisms i.e., plant-parasitic nematodes [9, 10]. Plant parasitic nematodes (PPNs) pose a major threat to the rice is also attacked by a wide array of nematodes [7, 11]. Over 200 species of plant parasitic nematodes have been reported to be associated with rice [12] and are becoming increasingly important in the rapidly changing production system of rice. Rice root-knot nematode, Meloidogyne graminicola Golden and Birchfield 1965 has emerged as a pest of international importance [13]. Among the major PPN species attacking rice, the root-knot nematode (RKN), Meloidogyne graminicola Golden and Birchfield, 1965 is considered as a major threat to rice alone has been reported to cause 50–75% yield loss under different conditions [14, 15]. For example in countries like China it has reported 85% [16], in Bangladesh under lowland rain fed rice losses can range between 16 and 20%, while in India, 16 and 32% under irrigated conditions and between 11 and 73% under flooded conditions [17, 18]. Since, its short life cycle, wider adoptability and wide host range, including many weed hosts that are commonly found in rice fields, make this species difficult to manage [13, 19].

2. Distribution of M. graminicola

2.1 Global distribution

Meloidogyne sp. a destructive nematode of rice it is widely distributed in various rice growing areas of the world; it was first described in 1965 from grasses and oats in Louisiana as M. graminicola [20]. M. graminicola distributed in different parts of the globe viz., Bangladesh, Philippines, China, Nepal, India, South East Asia, Burma, Laos, Thailand, Vietnam and USA. However, M. oryzae in Surinam of irrigated rice, Meloidogyne graminicola in Costa Rica, Cuba, Egypt, Ivory Coast, Nigeria, South Africa and Japan, M. javanica in Brazil, Egypt, Comoro Islands, Nigeria and Ivory Coast, M. arenaria in Nigeria, Egypt and South Africa and M. salasi in Costa Rica and Panama on upland rice [21]. Pakistan [22]. It is also found in the United States and Latin America, and was recently reported in Africa and Europe [23, 24, 25, 26, 27] (Figure 1).

Figure 1.

Global distribution of root-knot nematode in rice.

2.2 In India

Since, Meloidogyne graminicola was observed for the first time during 1969 in association with rice [28] in India, its prevalence has been recorded from all the rice growing states of the country namely, Assam, Andhra Pradesh, Andaman and Nicobar Islands, Bihar, Delhi, Himachal Pradesh, Haryana, Jammu and Kashmir, Karnataka, Kerala, Madhya Pradesh, Odisha, Punjab, Telangana, Tripura, Tamil Nadu, West Bengal and Uttar Pradesh [29, 30, 31]. The nematode was reported on irrigated rice in Andhra Pradesh, Telangana and Karnataka [32]. Severe infestation of M. graminicola occurs in upland and sometimes transplanted rice in north-eastern states, West Bengal, Odisha, Bihar, eastern Uttar Pradesh, Chhattisgarh, parts of Madhya Pradesh and Karnataka, Jammu, Punjab, Himachal Pradesh, Haryana, Delhi and Uttar Pradesh (Figure 2) [33, 34, 35, 36].

Figure 2.

Distribution of rice root-knot nematode in India.

3. Symptomptology of root-knot disease of rice

The sever infestation of Meloidogyne graminicola resulted in stunted growth, yellowing and patchiness in nursery as well main field. Under severe condition, reduced tillering, leaf size, poor and earhead emergence no earheads may be produced. It results in reduced grain yields. Under below ground parts of the plant formation of terminal hook or typical ring like spindle or bead/nodule shaped galls on the roots [37] (Figures 3 and 4). The infected plants exhibit reduced vigour, yellowing and sometimes curling along the midribs. The J₂ (second stage juveniles) cause responsible for induction of feeding sites that results in and hypertrophy and hyperplasia vascular tissues and cortex cells respectively [38]. High initial population of M. graminicola causes seedling wilt along with severe reduction in growth parameters, whereas, low population cause only reduction in growth parameters [39]. Characteristic hook like galls on roots, newly emerged leaves appear distorted and crinkled along the margins, stunting, chlorosis, heavily infected plants flower and mature early [24]. Yellowing, dwarfing and gall formation on the roots of rice plants. The degree of symptom manifestation differs with time of infection, age of the plants and load of inoculums [40]. The main symptoms caused by Meloidogyne graminicola are yellowing, stunting and gall formation on the roots of rice plants. The degree of symptom manifestation varies with inoculums load, time of infection, age of the plants, etc.

Figure 3.

Nursery and main field showing uneven yellowish patches and galls on root system.

Figure 4.

Symptoms of Meloidogyne graminicola and different galling pattern.

4. Biology of M. graminicola

M. graminicola is a meiotic parthenogen, with a haploid chromosome number of 18. M. graminicola completes its life cycle in 26–51 days in different periods of the year [41]. The J₂ stage requires 16 days at 26°C for converting into matured female and about 8–11 days at 26°C for egg to J_{2 (}second stage juvenile) [42, 43]. Studied the life cycle of M. graminicola and they found 24 days is enough to complete its life cycle. They reported that adult male and females were observed on day 10 and egg laying and release of juveniles were first observed on day 20 and 24, respectively [44], reported that life cycle of M. graminicola required 15–20 days to complete its life cycle in rice during different months in eastern Uttar Pradesh condition where temperature usually ranges between 22 and 40° C. Various scientists have been studied the life cycle of M. graminicola. According the study conducted by [45] the females of M. graminicola lay about 250–300 eggs in an egg sac inside the root tissues and the total duration of life cycle was about 25–28 days (Figures 5 and 6).

Figure 5.

Life cycle of rice root-knot nematode (M. graminicola).

Figure 6.

Biology of M. graminicola, (A) Infective J2, (B) J3, (C) J4, (D) Adult females (E) Adult male and (F) Female and egg.

5. Survival strategy

Survival of M. graminicola is mainly depends on the edaphic factors of soil and host factor. Various researchers have been reported that M. graminicola survival rate was more in moist and wet soil than air dried soil. Similarly the hatching of J₂ is highly inhibited by soil factor i.e., too wet and too dry soil [46, 47]. Application of nitrogen and phosphorus reduces the nematode population as compared to control plots (no fertiliser or compost). In contradict [48], found addition of nitrogen up to 40 kg/ha to the soil resulted in increased reproduction of M. graminicola. Application of additional phosphorus either alone or in combination with nitrogen also favoured nematode development. Rao andl Israel [49] reported maximum hatching of eggs of M. graminicola in water at 25°C and 30°C. At 15°C and 35°C hatching was reduced and at 20°C it was slightly less than that at 25°C [48], noticed that the juveniles entry in to the host was highest in soils with 32% moisture; similarly egg production were highest at 20–30% soil moisture and greatest juvenile invasion was observed at pH 3.5. Sandy or loamy, laterite soils or recent alluvial soils favour development of the nematode [49]. It has been observed that waterlogged condition in the direct seeded rice or transplanted crop had no detrimental effects on the survival of the endoparasitic stages [50]. Temperature of 22–29°C was found to be suitable for the prevalence of the nematode [32, 41]. Reported higher damage of root-knot in unflooded condition compared to the flooded condition at both ambient (30–40°C) and at high (40–45°C) temperature [51], reported that application of ammonia-based nitrogen fertiliser to the rice nursery bed may interfere with nematode attraction and thus reduce invasion, and the application of chemical nitrification inhibitors to rice nursery beds may decrease nematode invasion [52], studied the role of nutrient on infestation of M. graminicola and reported that roots supplied with a 100-fold lower supply of calcium nitrate (0.1 mM Ca(NO3)²) showed a higher level of nematode infection with higher root knot index [53], reported that at pH range between 6.5 and < 8.5 in the districts viz., Davanagere, Dakshina Kannada, Udapi, Uttar Kannada, Mysore, Kodagu and Haveri having moderate infection of M. graminicola with root-knot index of 3.0 [54], observed the higher nematode population at pH range 4.96–5.96 and soil organic carbon ranging from (1.50 to 1.59) and sandy loam soil in places viz., Chikadadkatte of Davanagere, Tuduru, Beguvalli, Megaramakki and Kadinabellu of Chickmagaluru district (586.33–841.00 J2/100 cc of soil).

6. Management

6.1 Host plant resistance

Resistant cultivars play an important role in sustainable management of nematodes. Since, they are very cheaper and economically friendly [55]. Exploration of resistance sources to M. graminicola in rice must be performed under favourable climatic conditions for maximum damage by this nematode [56, 57], screened 414 rice cultivars under artificially inoculating 15-day-old pot-grown seedlings with 100 second stage juveniles. Out of 414 cultivars, only two entries from breeding lines, 127-28-1-1-1 &183-6-1-1-3 were found resistant with score 2 [58], reported rice varieties Loknath 505 and M-36 resistant to the rice root-knot nematode, M. graminicola from Allahabad [59], evaluated 50 basmati rice germplasms against M. graminicola at crop research centre SVPUAT, Meerut. Out of 50 rice germplasms tested, the germplasms such as Pusa 1637-18-7-6-20 was found to be resistant with scale 2, while, 2 germplasms Shaan (Hybrid) and UPR 3805-12-2-7 were found to be susceptible with scale 4 [60], tested 87 cultivars of rice and 59 cultivars of wheat against M graminicola. The study revealed that two rice cultivars Achhoo and Naggardhan and two wheat cultivars HS 295 and VL 829 as resistant with 2 score. Out of 145 local cultivars, 32 and 45 local cultivars were found to be highly resistant and resistant respectively against M graminicola [61, 62], evaluated 20 rice genotypes against M.graminicola. Out of 20, only one genotype KMP-179 was found to be highly resistant which recorded least root-knot index (1.6) [63]. Screened 136 rice varieties, out of which, Zhonghua 11 (aus), Shenliangyou 1 (hybrid aus) and Cliangyou 4418 (hybrid indica) were highly resistant to M. graminicola under both pot and field conditions.

6.2 Biological control

Biological control is one of the component in Integrated nematode management system it improves the sustainable management of the nematode, soil health and quantity of rice. Bio-control being a ecofriendly and possible alternative to chemicals and safe for disease management i.e., nematode management, perhaps, it is free from toxic residual effects. There are various fungal and bacterial bioagents against M. graminicola and their application sequels in significant decrease in the nematode damage [64]. Application of the biocontrol agents such as Aspergillus niger, Pochonia chlamydosporia and Pseudomonas fluorescens proved to be more effective, and significantly reduced the nematode disease in rice [5]. Application of consortium of bio-control agents, P. fluorescens@20gm/sq.m + Trichoderma harzianum @ 20 g/sq. m was reported to be one of the best treatment in reducing the M. graminicolapopulation and increase in rice growth parameters [65]. Reported the application of combination of neem cake+ Vermicompost + Trichoderma spp. was found superior in comparison to other treatment in suppression of root gall formation on rice root in field [66], reported the application of mixtures of P. fluorescens strains with PF1 + TDK1 + PY15 signficantly reduced M. graminicola infestation when applied through seed treatment.

6.3 Cultural control

Burning of 15 cm deep rice hulls significantly reduce M. graminicola populations in the soil [67]. Summer ploughing and puddling of main fields before transplanting and Crop rotation with non-host crops like jute, mustard, chickpea and resistant varieties reduces M. graminicola infestation [33]. Crop rotation with non-host plants such as sweet potato, cowpea, sesame, castor, sunflower, soybean, turnip, cauliflower, jute, mustard and chickpea for at least 12 months are recommended to help manage rice root-knot nematode [26].

6.4 Chemical control

Root-dip and soil application of phorate 10G (25 mg a.i. /pot), carbofuran 3G (83.3 mg a.i./pot), carbosulfan 20EC (5 μL/pot) and chlorpyriphos 20 EC (6.25 μL/pot) reduces root-knot infestation in rice [68, 69], reported that application of Phosphonothioate 10G at 1 kg a.i./ha at 7 days prior to uprooting plus main field application at 45 days after transplanting at 1 kg a.i./ha resulted in maximum reduction in population of M. graminicola and increase in yield. Soil application and root dip of P. fluorescens or T. harzianum + carbofuran was found most effective and suppressed the gall formation (40–46%) and increased the yield up to 37–42% [70, 71], reported the fumigation of 1, 3-dichloropropene can help to reduce the number of nematodes before planting [72], adopted the Integrated Nematode Management Technology for the management of M. graminicola the results indicated that reduction in nematode population from 320 J₂/200 cc soil to 135 J₂/200 cc soil was recorded in cabrofuran (0.3 g) a.i/m² with more yield (4.72 tonnes/ha), followed by bioagents 165 J₂/200 cc soil (Pseudomonas fluorescence at 20 g/m²) with 4.67 tonnes/ha yield and 192 J₂/200 cc soil (Trichoderma viride at 4 g/200 cc of soil) with 4.29 tonnes/ha respectively [73], investigated application of bioagents along with nematicides found to be better in managing the infestation and increasing the yield of rice. Soil application of P. fluorescens at 20 g/m² + cabrofuran (0.3 g a.i/m²) found to be good in increasing growth of plant parameters viz., plant height (83.26 cm), root length (20.60 cm), maximum grain yield (44.1 q/ha) and least nematode population (132.67/200 g soil) with reduction of 79.34% nematode population.

7. Conclusion

Of late, Meloidogyne graminicola has becoming a major menace in rice. Due to change in global temperature, wider distribution, adoptability nature under adverse condition, wider host range and different survival stratagies denotes it has becoming a major menace in rice. Since there are many management practices available for nematode management but, sustainable management can be achieved by integration of cultural, physical, biological, host-plant resistance and usage of chemicals. The attention must be given to identify the different species involved in root-knot association, development of resistant varieties and development new nematicide for the management of this notorious pest in rice.