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Pests, Diseases and Abiotic Stress
Most of the mungbean cultivars have a yield potential of 1.8-2.5 tons/ha. However, the actual average productivity of mungbean hovers around 0.5-0.7 t/ha. Several factors constrain its yield, including biotic and abiotic stresses. Diseases not only decrease productivity but also affect the physical quality of seeds, leading to be totally unusable or unfit for human consumption. All the diseases collectively can lead to significant yield losses of up to 10%-100%.

Pests
Insect pests attack mungbean at all crop stages from sowing to storage and take a heavy toll on crop yield. Some insect pests directly damage the crop, while others act as vectors of diseases to transmit the virus.

Insects
Stem fly (bean fly), is one of the major pests of mungbean. This pest infests the crop within a week after germination and under epidemic conditions, it can cause total crop loss. Whitefly, B. tabaci is a serious pest in mungbean and damages the crop either directly by feeding on phloem sap and excreting honeydew on the plant that forms black sooty mould or indirectly by transmitting Mungbean yellow mosaic disease (MYMD). Whitefly causes yield losses between 17% and 71% in mungbean.

Thrips infest mungbean both in the seedling and in flowering stages. During the seedling stage, thrips infest the seedling’s growing point when it emerges from the ground, and under severe infestation, the seedlings fail to grow. Flowering thrips cause heavy damage and attack during flowering and pod formation. They feed on the pedicles and stigma of flowers. Under severe infestation, flowers drop and no pod formation takes place.

Spotted pod borer, Maruca vitrata (Fab.) is a major insect pest of mungbean in the tropics and subtropics. The pest causes a yield loss of 2–84% in mungbean amounting the US $30 million. The larvae damage all the stages of the crop including flowers, stems, peduncles, and pods; however, heavy damage occurs at the flowering stage where the larvae form webs combining flowers and leaves.

Nematodes
Cowpea aphid sucks plant sap that causes loss of plant vigor and may lead to yellowing, stunting or distortion of plant parts. Further, aphids secrete honeydew (unused sap) which leads to the development of sooty mould on plant parts. Cowpea aphid also acts as a vector of the bean common mosaic virus.

Other Pests
Bruchid is the most sever stored pests of legume seeds worldwide, damage up to 100% losses within 3–6 months, if not controlled. The cryptic behavior of bruchids where the grubs feed inside the legume seeds makes it easy to spread them through international trade.

Diseases
Viral, bacterial, and fungal diseases are of economic importance in South Asia, South East Asia, and Sub-Saharan Africa.

Viral Disease
Mungbean yellow mosaic disease (MYMD) is an important viral disease of mungbean, which causes severe yield losses annually. MYMD is caused by three distinct begomoviruses, transmitted by whitefly Bemisia tabaci. The economic losses due to MYMD account for up to 85% yield reduction in India.

Fungal Diseases
The major fungal diseases are Cercospora leaf spot (CLS), powdery mildew and anthracnose.

Dry root rot [Macrophomina phaseolina (Tassi) Goid] is an emerging disease of mungbean, causing 10–44% yield losses in mungbean production in India and Pakistan. The pathogen affects the fibrovascular system of the roots and basal internodes of its host, impeding the transport of water and nutrients to the upper parts of the plant.

Bacterial Diseases
Halo blight, bacterial leaf spot, and tan spot are important bacterial diseases.

Abiotic Stress
Abiotic stresses negatively influence plant growth and productivity and are the primary causes of extensive agricultural losses worldwide. Reduction in crop yield due to environmental variations has increased steadily over the decades. Abiotic stresses include extreme events and factors related to the atmosphere (heat, cold, and frost); water (drought and flooding); radiation (UV and ionizing radiation); soil (salinity, mineral or nutrient deficiency, heavy metal pollutants, pesticide residue, etc.) and mechanical factors (wind, soil compaction).

Salinity
Salinity affects crop growth and yield by way of osmotic stress, ion toxicity, and reduced nodulation which ultimately lead to reduced nitrogen-fixing ability. It is reported that salt stress significantly affected the performance of the root nodules in affected plants thereby reducing initiation, weight and nitrogen-fixing ability of the root nodules and also leading to inhibition of root colonization by Rhizobium. Excessive salt led to leaf injury and subsequently to reduced photosynthesis.

Temperature and drought stress
High-temperature stress negatively affects reproductive development in mungbean and affects all reproductive traits viz., flower initiation, pollen viability, stigma receptivity, ovule size and viability, fertilization, pod set, grain filling as well as seed quality. Temperature exceeding 42 °C during summer, causes hardening of seeds due to incomplete sink development.

Water stress
Mungbean requires a light moisture regime in the soil during its growing period, while at the time of harvest complete dry conditions are required. Since it is mostly grown under rainfed conditions, it is more susceptible to water deficiencies as compared to many other food legumes. Drought affects its growth and development by negatively affecting vegetative growth, flower initiation, abnormal pollen behavior and pod set. However, simultaneously, excess moisture or waterlogging, even for a short period of time, especially at the early vegetative stage may be detrimental to the crop.

Other abiotic stresses
Mungbean may also be affected by excess soil and atmospheric moisture during the rainy season which may lead to pre-harvest sprouting in mature pods. It deteriorates the quality of the seed/grain produced.

Integrated disease management
Using climate analysis tools delivered on the web can firstly help farmers to interrogate climate records to ask questions relating to rainfall, temperature, radiation, and derived variables to avoid some of the abiotic stresses. Deployment of varieties with genetic resistance is the most effective and durable method for integrated disease management, in the mean time focusing on yield, height, grain quality, market opportunities and seed availability. For pre-harvest sprouting (PHS), the development of mungbean cultivars with short (10-15 days) period of fresh seed dormancy (FSD) is important to curtail losses incurred by PHS.