A population of stunt nematodes (P36) was isolated from the soils of vegetable fields from Meerut district, India. Based on morphological, morphometric and molecular studies, the nematodes were identified as Merlinius brevidens. The Indian strains are characterised by having females with a body length of 0.57–0.64 mm and males 0.54–0.68 mm; lip region set off with of 4–7 annules and with six lips; stylet 13–14 µm long with prominent, posteriorly sloping knobs; vulva equatorial (V = 54–58); phasmids distinct, located in the anterior half of the tail; female tail (41–54 µm long, c = 11.3–15.0 µm, c’ = 2.8–4.9) sub-cylindrical with 27–32 annules and terminus hemispherical, almost smooth, slightly set off, bluntly rounded to sometimes acute to bulb-like; male tail (45–52 µm long, c = 11.2–14.7, c’ = 3.2–4.7) bearing well-developed bursa; spicules 18–23 µm long; gubernaculum 5–6 µm long. The Indian strain agrees well with the type material described from the USA. Flanking region D2–D3 segment of 28S rRNA of M. brevidens yielded 874 bp. We also sequenced for the first time the Internal Transcribed Spacer (ITS) rRNA of M. brevidens, which yielded 876 bp. The results of the phylogenetic studies supported the morphological and molecular data.

The novel technologies in all areas of agriculture have improved agricultural production, but some modern practices cause environmental pollution and human hazards. The recent challenge faced by advanced farming has been to achieve higher yields. Thus, there is an immediate need to find eco-friendly solutions. Among the various types of species being used as biocontrol agents, fungi of the genus Trichodermaare a very large group of microorganisms widely used as biocontrol agents against different kinds of plant pathogens. Trichoderma spp. are asexual, free-living organisms that are abundantly present in all types of agricultural soils. Recent studies have shown that Trichoderma can not only prevent diseases but also promote plant growth, improve nutrient utilization efficiency, enhance plant resistance, and improve the agrochemical pollution environment. Trichoderma spp. behaves as a low-cost, effective, and eco-friendly biocontrol agent for different crop species. This chapter provides information on Trichoderma as a biocontrol agent, its biocontrol activity, and plant disease management programs.

Agricultural soils and open fields from Western Uttar Pradesh (India) were surveyed to determine the presence of entomopathogenic nematodes. From the entomopathogenic nematodes isolated, Heterorhabditis isolates were selected and further characterized using morphological, morphometrical and molecular approaches. The results showed that three isolated nematodes were Heterorhabditis bacteriophora and were associated with Photorhabdus laumondii subsp. clarkei bacteria, while the rests were identified as Heterorhabditis indica. The biocontrol potential of H. bacteriophora against three agricultural pests was evaluated. Nematode infectivity experiments showed that the nematode isolates DH7 and DH8 were highly pathogenic against cotton bollworm (Helicoverpa armigera) and tobacco cutworm (Spodoptera litura), and less pathogenic against white grub (Holotrichia serrata) larvae. This study sets the basis for establishing new biocontrol agents to be used in pest management programs in India.

An insect parasitic nematode belonging to the genus Oscheius was recovered from the agricultural soils from the Hapur district in western Uttar Pradesh, India. Morphological studies on this species exhibited its high resemblance with two Pakistani species: Oscheius siddiqii and O. niazii. No molecular data are available for these taxa but, morphologically, both species do not differ significantly from our strains and each other. Hence, these nematodes can be considered conspecific, and the correct name for this taxon is O. siddiqii, the first described species. The phylogenetic analyses of the ITS-, 18S-, and the 28S rDNA sequences showed that O. siddiqii is a sister taxon to the group formed by Oscheius microvilli, O. myriophilus, O. safricanus, and several unidentified Oscheius species. Additionally, our analyses show that based on molecular and morphological data, the species Oscheius rugaoensis and O. microvilli cannot be distinguished from O. chongmingensis and O. myriophilus, respectively, and are thus considered junior synonyms of these taxa. Furthermore, the available data are not sufficient to evaluate the status of Oscheius basothovii and O. safricanus, which are, in consequence, considered species inquirendae. These findings highlight the necessity of the proper morphological and molecular characterisation of the described Oscheius species.

A population of a nematode species belonging to the genus Oscheius was isolated in western Uttar Pradesh, India. Morphological and morphometrical studies on this species showed its high similarity with six species described previously from Pakistan (Oscheius citri, O. cobbi, O. cynodonti, O. esculentus, O. punctatus and O. sacchari). The molecular analysis of the ITS1-5.8S-ITS2 rDNA sequences of the Indian population and the six species described from Pakistan showed that all the sequences are almost identical. Thus, based on morphological and molecular characteristics, all of the six above-mentioned Pakistani species and Indian strain do not differ from each other, hence can be considered synonyms. The correct name for this taxon is the first described species O. citri. Additionally, the phylogenetic analysis of the 18S rDNA and the 28S rDNA sequences showed that Oscheius citri is sister to the clade formed by O. chongmingensis and O. rugaoensis from China. The high similarity of morphological and morphometric characteristics of O. citri and other species, O. maqbooli, O. nadarajani, O. niazii, O. shamimi and O. siddiqii, suggest their conspecificity; however, lack of molecular data for these species does not allow this hypothesis to be tested.

Two cultured populations of Steinernema surkhetense are described from India. Morphologically and morphometrically this material agrees with other species of the Carpocapsae-group (presence of short juveniles), especially with S. surkhetense. The morphology was somewhat similar to the original description with the distinguishing feature being the presence of anal swelling in second-generation female specimens but absent in the original specimens. The morphometric measurements were in close proximity to those in the original specimens and the PCA analysis of important morphometric characters demonstrated some variability within the test populations. Molecular studies based on 28S and ITS rDNA confirmed the Indian material is well conspecific Nepali populations of S. surkhetense, however, with Nepali populations, two base pair differences were observed at 376 and 713 positions only in ITS rDNA gene. We performed a molecular and biochemical characterization of the bacterial symbiont of S. surkhetense and the symbiont is closely related to Xenorhabdus stockiae, which is widespread among South Asian nematodes from the ‘‘carpocapsae’’ group. Finally, we mapped its geographical distribution using a meta-analysis of the ITS GenBank records. The distribution of S. surkhetense based on a meta-analysis of the GenBank records showed its presence in the three Asian countries—India, China, and Nepal, with maximum records from the Indian subcontinent. This species is indigenous to the Indian subcontinent, thus could be tested and later used in the biocontrol of insect pests in India