**8. Crop protection role in promoting underutilized grasses**

Crop protection constitutes one of the most vital branches of agricultural science which keeps on devising biologically viable ways and cost-effective means for controlling various types of diseases, insect-pests in order to prevent significant damage by keeping harmful organisms below threshold levels. To prevent a severe disease outbreak comprises maintaining a healthy and vigorously growing crop. Each individual plant in the field requires optimum water and fertilizer quantity, as well as an aerated, well-drained soil but lacking any of these factors, the crop may become stressed ultimately more susceptible to disease. A study revealed that microbial diseases are responsible for the ultimate crop losses up to 16%, out of these 16% microbial losses almost 70–80% were due to fungal pathogens. It is estimated that more than 100,000 plant diseases can be caused by 8000 reported fungal species. As far as the underutilized grasses needs to be maintained by characterization and research on its agronomic factors, still there is a dire need to explore the pathogens causing mild to severe diseases ultimately suffering a huge loss in its production and quality traits. A few of the major crops may responsible for nutrition as well as food security that ultimately leads to keep the agriculture system vulnerable to various biotic and abiotic stresses due to the lack of genetic diversity in these crops. As far as diseases are concerned, there may be fungal and viral diseases that may be challenging to adopt in the underutilized grasses [15–18].

Besides numerous diseases, a few need more attention as to be more severe in the grasses which must be investigated to find out biologically viable solution for keeping these below the threshold level. Rust caused by the species of genus Puccinia and is obligate plant pathogen. This genus contains more than 4000 species based on their hosts. Considering lemongrass as an example of underutilized grasses the rust caused by *Puccinia nakanishikii* Dietel more sever in warmer and more humid areas. It produces light brown pustules on both the lower and upper surfaces of leaves. The spores dispersal through wind may spread the disease on larger scale. Unfortunately, there is still the lacking research on the management strategies of this disease on lemongrass and is a dire need to address this issue to overcome the pathogen potential. Furthermore, *Helminthosporium cymbopogi* another fungal pathogen causing a sever disease of grasses including lemongrass known as leaf spot. Similarly leaves curling and browning caused by brown tip disease is due to the low water content in the leaves. Foliage blight is another fungal disease caused by *Curvularia andropogonis* (Zimm.) infecting mostly grasses led to the considerable yield losses. The common management practice to control these fungal diseases is application of 1% Bordeaux mixture or 0.3% Zineb three times with an interval of fifteen days. Similarly, 0.2–0.3% Mancozeb can be an alternative fungicide application thrice in the season with 15 days interval [19–23].

Similarly blast is another important fungal disease on grasses especially on millet caused by *Pyricularia grisea* lead to sever grain losses 56–80% while upto 35% losses were reported in 1000-grain mass. Millet is vulnerable to this pathogen from seedling till its grain formation. Commonly the symptoms are spindle shaped lesions of

different sized, generally the spots appear initially with yellowish margins and gray centers. The lesions later on turned to whitish gray and also olive gray growth of fungus may appear on the lesions. Seed treatments with Tricyclazole may be effective to overcome the primary seed born inoculum. Later on, fungicide application on ear appearance and after 10 days interval should give better results. It has been reported that biological control agent 0.6% *Pseudomonaas fluorescens* used as seed treatment following two later spays of the same bio-agent may constitute a good alternative to chemical fungicides for underutilized grasses [24–26].

Among nematode disease cereal cyst nematodes among one of the oldest genus named Heterodera are the more important that may infect small cereal grain crops like oat, barley, wheat, rye, and triticale. Cereal cyst nematodes complex widely distributed on family Poaceae includes several species. Among these species oldest reported specie was *Heterodera avenae* followed by *H. latipons*, then H*. hordecalis* in North Europe, furthermore H. filipjevi in eastern Europe, up till now 11 species of genus *Heterodera* has been reported. Among these 11 species three of them i.e. *H. avenae*, *H. latipons*, and *H. filipjevi* considered economically important on cereals globally [25–28].

Generally, the best management practice to normalize the effect of cereal cyst nematode may include crop rotation with a non-host crop. The eggs of cyst may become dormant inside the cyst for many years but have a very narrow host range, therefore rotation led to the best cultural practice. Furthermore, clean fallows, sanitation of fields, weed control, sowing time to escape egg hatching and trap cropping should be effective. Use of resistant varieties and chemical nematicides directly minimize the population density of nematode. Studies revealed that the use of nematophagous fungi should be an alternative of chemical control as to target the cyst nematodes with the use of these biological control agents.
