**1.6.2 Area and production**

India is reportedly the largest pulse growing country in the world both in terms of area as well as production covering 43.30 per cent of land area under pulses with 33.15 per cent production. In another report, it has been described that India is the largest producer and consumer of pulses in the world accounting for 33 per cent of world's area and 22 per cent of world's production of pulses. Green gram is one of the most widely cultivated pulse crops after chickpea and pigeonpea. The major producing states in India are Andhra Pradesh, Orissa, Maharashtra, Madhya Pradesh and Rajasthan accounting for about 70 per cent of total production.

Reliable production statistics for mung bean are difficult to obtain, as its production is often lumped together with that of other *Vigna* and *Phaseolus* spp. India is the main producer, with an estimated production in the late 1990s of about 1.1 million t. China produced 891,000 t (19per cent of total pulse production in China) from 772,000 ha in 2000. No mung bean production statistics are available for Africa. China exported 110,000 t in 1998, 290,000 t in 1999 and 88,000 t in 2000. All mung bean produced in India is for domestic consumption. In most parts of Africa where there are Asian communities, mung bean food products are sold in the cities (Mogotsi, 2006).

In India it is cultivated in two seasons: *kharif* and summer. However, peak market arrivals are from September to October (*kharif*) and June to July (summer). Green gram is mostly grown as a *kharif* crop (monsoon season) in the states of Rajasthan, Maharashtra, Gujarat, Karnataka, Andhra Pradesh, Madhya Pradesh and Uttar Pradesh; but, in Tamil Nadu, Punjab, Haryana, Uttar Pradesh and Bihar it is grown as a summer crop. Green gram is a short duration crop; the canopy closes in earlier than in cereal crops. Therefore, the critical period for crop-weed interference is limited to the first 30 days after sowing. However, the presence of weeds during this period may lead to 20 to 40 percent reduction in yield. The most phenomenal way of reducing weed infestation include preventive measures like use of clean crop seed and pre-planting destruction of existing weeds by tillage. In the standing crop, one inter-row hoeing and weeding at 25 to 30 days after sowing is good enough to check potential losses. Sometimes in the monsoon crop, due to incessant rains, tillage

Insect Pests of Green Gram *Vigna radiata* (L.) Wilczek and Their Management 203

The population of jassds and whiteflies can be estimated by the sudden trap method using a cubical iron-frame trap of 45cm x 45cm base and 60cm height clothed in high density polythene or covered by muslin cloth on three sides, while one side and the top can be clothed with high density polythene for viewing the adults captured in the trap. This is possible when the crop is 35 to 40 day-old; thereafter, we have to rely on visual count technique as it is not feasible to use the sudden trap because as per agronomical practices the spacing is recommended as 30cm between the rows and 10cm between two pants in a row; though, we may go for a spacing of 45cm (row to row) by 15cm (plant to plant in a row). Yes, an aspirator should be used to suck the adults for a reliable count. The few adults that might escape while counting from each tagged plant or replicate is a common error and will be taken care of if the sample size is more. The jassid nymphs move sideways but do

Data from visual counts can be homogenized by following the square root transformation method, especially when zero counts are recorded. We add 0.5 or 1.0 to the visual count data and find the square root before analysis that has to be retransformed after analysis for interpretation. In case of percentage data, if the percentage values range between 30 and 80, usually arc sine (angular) transformation would not be required; however, if the percentage values happen to be less than 30 and/ or more than 80, then angular transformation is

Green gram being an indeterminate plant, vegetative growth and flowering go together when the plant is 35 to 40 days of age; hence, using a suction trap (battery operated/electric) might not be successful, as it will cause more harm to the plant and at the same time disturb the insects. We can use the suction trap if the field/plot size is large so that sampling can be taken from distant areas within the field being observed without disturbing the insect

ii. The associated natural enemies like syrphid flies, coccinellids and others, can be recorded by the visual/sight count technique from the same number of plants per replication (1/5th of total population) randomly tagged, during early hours of the day. Observations can be taken to study the predator-prey function under caged

iii. Observations can be taken on a weekly basis or a 10-day basis and the prevailing abiotic conditions of the atmosphere can also be recorded accordingly to work out the correlation coefficients between the populations and the abiotic factors of the

It is true that correlations do not establish the cause and effect relationships and must be interpreted with caution. Therefore, further working out the simple regression lines or linear regressions through regression equations enables us to know the effect of the abiotic factors (independent variable) on the population (dependent variable). Data so collected and collated over many years (at least for 5 years in succession) will give a good understanding

Y = a + bX

not leave the foliage while observing, hence their count is reliable.

required before analysis of data.

species on adjacent plants.

conditions.

environment.

of the population trend.

The equation of a line of regression (Y on X) is given as:

operations are not feasible; hence, the use of pre-plant incorporation of fluchloralin or pendimethalin at the rate of 0.75 to 1.0 kg per hectare is recommended.

#### **1.6.3 Cropping systems**

The common crop rotations followed in India include: green gram – mustard; green gram – safflower; green gram – linseed; and green gram – wheat. In *kharif*, intercropping with maize, pearl millet, sesame, pigeon pea, and cotton is common. Spring or summer green gram is grown as a catch crop. The crop sequences that have been successful are green gram – maize – wheat, green gram – rice – wheat, green gram – maize – toria – wheat, green gram – maize – potato – wheat. In spring planted sugarcane, it is also grown as an intercrop. During *rabi*, it is grown in rice fallows of southern and south eastern region (ICAR, 2006).


The area (m-ha), production (m-t) and Productivity (kg/ha) in India

Source: Directorate of pulses development Bhopal
