System of crop intensification for more productive, resource-conserving, climate-resilient, and sustainable agriculture: experience with diverse crops in varying agroecologies

With continually increasing demand for food accompanied by the constraints of climate change and the availability and quality of soil and water, the world’s farmers are challenged to produce more food per hectare with less water, and with fewer agrochemical inputs if possible. The ideas and methods of the system of rice intensification which is improving irrigated rice production are now being extended/adapted to many other crops: wheat, maize, finger millet, sugarcane, tef, mustard, legumes, vegetables, and even spices. Promoting better root growth and enhancing the soil’s fertility with organic materials are being found effective means for raising the yields of many crop plants with less water, less fertilizer, reduced seeds, fewer agrochemicals, and greater climate resilience. In this article, we review what is becoming known about various farmer-centred innovations for agroecological crop management that can contribute to agricultural sustainability. These changes represent the emerging system of crop intensification, which is being increasingly applied in Asian, African, and Latin American countries. More research will be needed to verify the efficacy and impact of these innovations and to clarify their conditions and limits. But as no negative effects for human or environmental health have been identified, making these agronomic options more widely known should prompt more investigation and, to the extent justified by results, utilization of these methodologies

SEASONAL BIOLOGY OF BIHAR HAIRY CATERPILLAR, SPILARCTIA OBLIQUA WALKER (LEPIDOPTERA: ARCTIIDAE) ON CASTOR, A PRIMARY FOOD PLANT OF ERI SILKWORM

The biological aspects of Bihar hairy caterpillar, Spilarctia obliqua Walker infesng castor, Ricinus corninunis (Non-bloomy red variety) were studied in different seasons at RSRS, Mendipathar. The biological parameters like larval period, pupal period, total life cycle, fecundity, hatchability, incubation period, and adult longevity were recorded during four seasons, viz. March- April, June-July, October-November and December-January. Egg incubation varied from 6.5 -10.5 days, the shortest in October-November and longest iii December-January. The season has no effect in the egg hatchability of the insect. The larval period varied from 24 days (June-July) to 44 days (December-January). Similarly, the total life cycle (egg to adult) took only 39.6 days in June- July and it was prolong up to 70 days during December-January. The fecundity was recorded maximum in October-November (987 eggs) and lowest in December-January. (654 eggs). Adult longevity was more or less same in all the seasons

STUDIES ON THE OCCURRENCE OF BIPUPATE AND TRIPUPATE COCOONS IN A BIVOLTINE HYBRID, SK6 x SK7 OF THE MULBERRY SILKWORM, BOMBYX MORI L.

In mulberry silkworm, occurrence of bipupate cocoon is a common phenomenon but tripupate cocoon formation is rare. It is formed by the joint labour of two or three larvae. The formation of bipupate and tripupate cocoons is a phenomenon determined by ontogenetic circumstances depending upon the amount of space available to the spinning worms. Studies conducted during autumn crop rearing revealed that the occurrence of bipupate and tripupate cocoon was 3.94% and 1.0% out of the total cocoon observed. In bipupate cocoons, the highest frequency of association was observed in M: F (66.85%) and lowest was in F: F (13.92%). In tripupate cocoons, the highest frequency of association was in 2M: 1F (43.13%) and lowest was in 3F (23.28%). The information on the occurrence of tripupate cocoons in other silkworm is scanty

EVALUATION OF SOME MULBERRY VARIETIES FOR YIELD AND QUALITY THROUGH BIOASSAY IN MANIPUR, NORTH EAST INDIA

Eight mulberry varieties, viz., BC259, K2, S1, S146, S1635, TR4, TR10 and V1 were studied for their leaf yield and rearing performance in Manipur. Out of these varieties, V1 has yielded significantly highest leaf yield followed by S1635 and S146 respectively and the yield of BC259, K2, TR10 and TR4 being at pat. The lowest leaf yield was recorded in S1. Bioassay conducted through silkworm rearing revealed that the highest cocoon yield (both by weight and number) was recorded in V1 followed by BC259, S1635, K2 and S1. Among these, S1 and S1635 showed higher cocoon shell percentage while BC259 showed higher cocoon weight. Hence, V1, S1635, BC59, K2 and S1 are equally good in leaf and cocoon yield and are superior to other varieties of mulberry tested

BIOECOLOGICAL STUDIES OF ANOAKTASAR SILKMOTH, ANTHERAEA FRITHII MOORE IN NORTH EAST INDIA

Antheraea frithii Moore, an oak fed silk moth constitutes a part of the wild silk moth genetic diversity. Survey in the forest of North-East India records the availability of this wild silk moth in the oak growing areas of this region. In view of understanding the silk moth, the collection, conservation in ex-situ condition, bioecological parameters, characteristic features of the different stages and utilization of this particular silk moth were undertaken and presented in this paper. The silk moth behaves as bivoltine or trivoltine. Self coupling of moths occurs to the tune of 45 to 65% in captive condition inside spacious wire mesh cages (6' x 6' x 6.5"). The female moth lays 200250 eggs. Observation on the variations in morphological characters of the various developmental stages indicates the possibility of occurring natural hybridization among wild population. The study on the ex-situ conservation of this wild silk moth records the average values of the eight important parameters viz., fecundity, hatching percentage, cocoon yield, ERR96, cocoon weight, shell weight, shell ratio% and average single filament length during the three crops as 215-235 eggs, 65.22-75.00%, 40-50 cocoons/dfil, 26.66-32.00%, 4.52-4.60g, 0.51-0.55g, 11.25-11.96% and 625-665 m respectively. The present study opens a new vista for exploiting the particular wild silk moth for commercial production of tasar cocoons

PHENOLOGY OF WILD CASTOR, RICINUS COMMUNIS L. AND ITS PALATABILITY FOR ERI SILKWORM, SAMIA RICINI (DONOVAN)

Castor, Ricinus communis L. is the main food plant of eri silkworm, Sarnia ricini (Donovan). The present investigation in wild castor revealed differences in phenological events like germination, vegetative growth , formation of spike and capsules, defoliation of leaves and plant death at plains and hills in northeastern region of India. Maximum castor fruits mature from May (16.1%) to July (32%) at plains and from September (24.6%) to October (12.2%) at hills. Palatability of an eri silkworm was tested on wild population and revealed effective rate of rearing (ERR) 76.43% and 79.52% in plains and hills, respectively