Survey, incidence and field study of Purpureocillium sp. in different crops

Introduction

Plants are an incredibly important kingdom of organisms having amazing ability to make their own food from carbon dioxide in the atmosphere and with the help of chlorophyll content. They provide the foundation of many food webs and also animal life would not exist if plants were not around. However, the potentiality of plant to function normally and to produce food for mankind and others has been disrupted by the attack of different pathogens which causes disease. A plant disease is usually defined as abnormal growth or disfunction of a plant. Diseases are the result of some disturbance in the normal life process of the plant. In other words, any malfunctioning of host cells and tissues that results from continuous irritation by a pathogenic agent or environmental factors that leads the development of the symptoms. Disease may be result of the any living or non-living causes. Biotic diseases are caused by the living organisms like fungi, bacteria, viruses, nematodes and phytoplasma like organisms. Abiotic diseases are caused by non-living environmental conditions such as soil compaction, wind, frost, nutritional abnormalities, mineral toxicity and pesticide exposure etc. Purpureocillium sp. is a common saprophytic, filamentous fungus. It has been isolated from a wide range of habitats including cultivated and uncultivated soils from forests, grassland, deserts, estuarine sediments and sewage sludge. It has been found in nematode eggs and occasionally from females of root knot and cyst nematodes. In addition, it has been frequently detected in the rhizospheres of many crops. These species can grow at a wide range of temperatures from 8°C to 30°C with optimal growth in the range of 20° to 25°C. It has a wide pH tolerance and can grow on a variety of substrates (Paladiya et al., 2026). Purpureocillium sp. has shown promising results as a biocontrol agent to control the growth of destructive root knot nematodes and other soil-borne pathogens (Anusha, 2014). Looking into the severity of root knot nematodes and other soil borne pathogens infestation on various crops and farmers inclination towards the biocontrol agents for the management of these diseases. Thus, the present study has been taken up with the specific objectives.

Materials and Methods

An intensive survey was carried out to know the appearance of Purpureocillium sp. in different solanaceous crops viz., Tomato, Chilli, Brinjal and Okra in growing areas of Navsari, Valsad and Tapi districts of South Gujarat. Samples of collected soil were analyzed. For this purpose two talukas in each district were taken and in each taluka, two villages were taken for the assessment of the disease. The soil samples were collected by using random sampling method from the disease as well as healthy crop rhizospheres and methodology was followed as suggested by Pau et al., 2012. Soil samples were collected from the rhizosphere of diseased infected plant at the depth of 12 to 15cm. Each sample was taken separately in polythene bags and tied with a rubber band and labelled immediately. Information pertaining to the locality, GPRS location and stage of the crop was recorded. Root knot index was calculated by following the grade suggested by Taylor and Sasser (1978) For the assessment of the Nematode gall index, randomly 5 locations in each field and total 100 plants were selected.

Result and Discussion

Roving survey was carried out during the year 2019-20 to assess the presence of nematophagous fungi Purpureocillium sp. and observation recorded on incidence of root knot nematode in major crops viz., tomato, chilli, brinjal and okra growing districts of Navsari, Valsad and Tapi of South Gujarat. Incidence of root knot nematode was calculated by using nematode gall index as suggested by Taylor and Sasser (1978). Among all the districts surveyed of South Gujarat the Purpureocillium sp. was more prevalent in Tapi district. Various locations had different soil and climatic conditions and crops were at different growth stages during the field visit. The different crops were surveyed for prevalence of Purpureocillium sp. and occurrence of root knot nematode. In Navsari district, survey was carried out in four locations which had medium to black soil type and crops like tomato, chilli and brinjal were in flowering to fruiting stage. However, Purpureocillium sp. was found only in Abrama village of Jalalpor taluka. The respective sample was collected and coded as P-1, which had root knot incident. Mandir, Sadakpor and Soldhara areas are other locations where, the root knot nematode was not noticed. Purpureocillium sp. was isolated only from Abrama location and it was called as Abrama isolate (P-1). In Valsad district, total four locations were surveyed, among them Purpureocillium sp. was found only at Baroliya village of Dharmpur taluka. The isolate was collected and coded as P-2. In this location, the soil was black and brinjal crop was in flowering to fruiting stage. Root knot nematode incidence was observed at Baroliya village only of Dharmpur taluka. However in other locations viz., Bamti, Ozarda and Panas root knot nematode incidence was not observed. Purpureocillium sp. was isolated only from Baroliya location and it was called as Baroliya isolate (P-2). In Tapi district, out of four locations surveyed Purpureocillium sp. was found in two locations namely Siker and Ambach village of Valod taluka and it was coded as P-3 and P-4 respectively. The soil was medium to black soil type and okra and tomato crops were in flowering to fruiting stages. Root knot nematode incidence was observed only in Ambach location. In other villages viz., Siker, Borkhadi and Balpur root knot nematode incidence was not observed. The Purpureocillium sp. was isolated from two locations in Tapi district and they were called as Siker (P-3) and Ambach (P-4) isolates. Overall the survey results indicate that Siker and Ambach are the two locations of Tapi district, which can be considered as the main spot region for the presence of Purpureocillium sp. However, least presence of Purpureocillium sp. was found in Abrama village of Jalalpor taluka of Navsari district and Baroliya village of Dharampur taluka of Valsad district from which bioagents were isolated (Table 1 and Plate 1). Similar research findings were made by Anusha et al. (2017) while, working on the solanaceous fruit crops like tomato, okra, chilli and brinjal. They isolated seven different strains of P. lilacinus from different districts of Northern Karnataka.

Acknowledgement

AcknowledgementAuthor is extremely thankful to the Department of Plant Pathology, N. M. College of Agriculture, NAU, Navsari (Gujarat) and Dr. Prashant B. Sandipan (Major Advisor), Main Cotton Research Station, NAU, Surat (Gujarat) for providing the binding proficiency and other decisive measures for the conducting the experiment.

References

1. Anusha B. Mass production of Paecilomyces lilacinus (Thom) Samson and bioefficacy against root-knot nematode infecting tomato [thesis]. Dharwad: University of Agricultural Sciences Dharwad; 2014.
2. Anusha BG, Kulkarni S, Harlapur SI. Morphological and biological variability of different isolates of Paecilomyces lilacinus against root knot nematode in tomato. Int J Curr Microbiol Appl Sci. 2017;6(10):1243-1257.
3. Paladiya S, Sandipan BP, Patel RK, Ruwali P, Sharma N, Kodavala P. Purpureocillium sp. -A potential antagonist against different phytopathogens. Int J Agric Food Sci. 2026;8(5):244-246.
4. Pau CG, Leong S, Wong SK, Eng L, Jiwan M, Kundat FR, et al. Isolation of indigenous strains of Paecilomyces lilacinus with antagonistic activity against Meloidogyne incognita. Int J Agric Biol. 2012;14:197-203.
5. Taylor AL, Sasser JN. A world perspective on nematology: the role of the society. In: Veech JA, Dickson DW, editors. Vistas on nematology. Hyattsville (MD): Society of Nematologists; 1978. p. 211.