• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.41-45
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• 2000

The effect of topical application with hydrocortisone on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at higher concentrations along with other enhanced larval, cocoon and adult parameters. This suggests that hydrocortisone can be used effectively for commercial silkworm rearing. The larvas period was significantly increased in all the treated groups with increased female cocoon weights, its shell weights and male cocoon shell weight at 20$\mu\textrm{g}$/ml treated group. Filament length, weight and denier were increased significantly in all the treated groups. Moth emergence percentage, length of the ovariole, eggs per ovariole, fecundity and rind hatching percentage were unaffected when compared with that of the carrier control group. This suggests that hydrocortisone in addition to affecting larval growths also affect silk crop.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.555-562
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• 2022

We raised the white-spotted flower chafer, Protaetia brevitarsis seulensis, from the larvae stage using a fermented mulberry sawdust-base diet at 25℃ and 16:8 h light:dark photoperiod. First, we determined the optimal density of the neonate larvae to be introduced into a rearing box (543 × 363 × 188 mm). The survival rates of the larvae were higher than 80% at 90 days after rearing at 100-175 larval densities but reduced by more than 10% at 200 larval density. The larval weights at 100 to 150 larval densities were similar; however, the weights at 175 and 200 larval densities were lower than those at 100 larval densities, indicating that the rate of weight gain increased under lower density. Based on these results, we inferred that 100-150 larvae was the optimal density. Second, we investigated the storage conditions of the last instar larvae under low temperatures. Four weight groups (1.8-2.0, 2.0-2.3, 2.3-2.5, and 2.5 g) of larvae were stored at 4, 8, and 10℃, respectively. All the larvae at 4℃ died 70 days after storage, whereas 80% of the larvae survived at 8℃ 70 days after storage, indicating that high larval weight was associated with high survival rates. The adults that emerged from larvae with more than 2.3 g and stored for up to 50 days at 4℃ laid few eggs. However, the adults that emerged from all larval weight groups stored for 70 days at 8℃ and 10℃ laid several eggs successfully. Based on these results, we inferred that the last instar larvae with more than 2.3 g could be stored for 30-50 days at 8℃.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.114-119
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• 2005

Larval survivorships, growth rates, developmental rates, and emergence rates of Cloeon dipterum were studied under four constant temperatures $(10^{\circ}C,\; 15^{\circ}C,\;20^{\circ}C,\;and\;25^{\circ}C)$ in the laboratory. Larval mortalities were relatively higher during the initial one-week period, but those tend to be stabilized as the experiments proceed. Judging from the growth and develop-mental rates, estimated optimal temperature for larval growth and development lies between $20^{\circ}C\;and\;25^{\circ}C$. Estimated larval period for emergence is less than 100 days.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.175-182
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• 2002

A new high yielding mulberry genotype, Victory-1 (V-1) was recommended to the field for irrigated areas by Central Sericultural Research and Training Institute (CSRTI), Mysore during 1996-1997. As K-2 and S-36 mulberry genotypes are already in the field, a study on the comparative performance of V-1, 5-36 and K-2 varieties, in terms of leaf yield, yield attributes, leaf moisture and moisture retaining capacity and their impact on silkworm rearing was carried out under Telangana conditions of Andhra Pradesh during 1999-2001. Among the three genotypes the leaf yield was found to be significantly (P < 0.01) higher in V-1 (64,130 kg/ha/yr) followed by S-36 (44,064 kg/ha/yr) and K-2 (23,990 kg/ha/yr). The maximum leaf moisture was also observed in V-1 (71.84%) compared to S-36 (66.86%) and K-2 (64%). The moisture retaining ability was more in V-1 (70.17%) followed by S-36 (66.20%) and K-2 (60.08%). The yield attributes were found to be significantly (P < 0.01) enhanced in V-1 over S-36 and K-2. Silkworm rearing results (bioassay) indicated a significant (P < 0.01) reduction in larval duration and improvement in larval weight, effective rate of rearing by number and weight, single cocoon and shell weights and shell ratio in the silkworm lots fed on V-1 variety followed by S-36 and K-2. Hence, in this study, V-1 was found to be superior among the three varieties studied.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.75-78
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• 2015

The white-spotted chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae), is an economically important insect in Korea. Traditionally, it has been regarded as a medicine for preventing liver-related diseases and suppressing liver cancer. Recently, this beetle was enlisted as a temporal food ingredient by Korean Ministry of Food and Drug Safety. Therefore, this beetle is focused as a one of the important insects that are commercially reared and sold in Korea. As the economic importance of this beetle is growing, the suitable rearing conditions are needed for more detailed investigation. In this study, we compared three temperature conditions and two food additives, rice chaff and soybean cake, for its effects on the body weight change of third instar larvae of P. brevitarsis. Temperature is a major environmental factor that has tremendous effects on rearing insects. In additions, rice chaff and soybean cake are byproducts of other agricultural activities. Therefore, it is easy to get, and the price is comparatively low. However, they still have meaningful amount of nutrients. With four different kinds of feed and three temperature conditions on the third instar larvae of beetles, the body weight change was tracked for 14 wk. We concluded that 27.5℃ is the optimal temperature to rear the third instar larvae among three temperatures (25, 27.5, and 30℃). Among four different feeds, conventional fermented oak saw dust with rice chaff and soybean cake was the best feed for larval weight gain during 14 wk. However, feed with soybean cake at 30 ℃ was the best condition for rearing P. brevitarsis larvae when temperatures and feeds were compared at the same time.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.33-41
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• 2004

The type of trichomes, their density and pattern of distribution on leaves of 16 genotypes of mulberry, belonging to both diploid and polyploid categories, were studied by scanning electron microscope. The present investigation was undertaken to find out the relationship of physical attributes, especially the density and trichome types with higher acceptability and better rearing performance by the silkworm Bombyx-mori L. Two types of trichomes glandular and non-glandular types were observed on both the leaf surfaces of all the mulberry genotypes studied. In general, greater densities of trichomes were observed on the abaxial surface than the adaxial surface of leaves in most of the genotypes. Distribution of glandular trichomes were more in abaxial surface and non-glandular trichomes were more in adaxial surface. Overall, distribution of glandular and non-glandular trichomes per unit area of leaf did not follow any regular pattern. When leaves of those genotypes were fed to silkworms, trichome density was found to be significantly negatively correlated with the survival of larvae i.e., effective rate of rearing, but trichome density did not influence the economic characters of rearing. As the distribution of glandular trichomes (GT) and non-glandular trichomes (NGT) did not follow any definite pattern, no relation could be established between the GT and NGT densities with silkworm rearing performance. However, the ratio of GT and NGT in a particular genotype influenced the rearing parameters, higher the ratios better the rearing performance. High GT and NGT ratio (＞1.00) was found positively significant when correlated with economic parameters viz., larval weight, single cocoon weight and single shell weight. The study is useful in screening different mulberry genotypes for their better acceptability to silk-worm and higher rearing performance at the early stage of selection without actually conducting the rearing.

• Journal of Life Science
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• v.29 no.9
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• pp.996-1001
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• 2019

Edible insects are reported to be rich in protein, minerals and vitamins, and much attention has been paid to them as a future food source. In Korea, they were massively reared and sold. In order to enhance the market value of edible insects for industrialized mass production, it is important to develop the safe and nutritious feed sources for rearing them are needed. In this study, a chlorella-free control feed (Exp1) and six experimental feeds supplemented with 0.5~2.0% liquid or powder types of chlorella were formulated. Protaetia brevitarsis and Allomyrina dichotoma, registered as food ingredients in Korea, were fed with the designed feeds and parameters of growth including larval survivorship, larval body weight, and larval period were analyzed. When chlorella added, larval survivorship was increased 2~13%(p>0.05) and 9~22%(p<0.05) in each beetle compared to the control. Interestingly, the larval period of chlorella powder-added groups was shortened by 24 days (Exp3, p<0.05) in P. brevitarsis and 19 days (Exp4, p<0.01) in A. dichotoma. Meanwhile, some parameters, crude protein, crude fiber, copper, zinc, potassium, magnesium, and phosphorous, in chlorella-added groups of P. brevitarsis were also higher than the control group. Therefore, chlorella could promote the larval growth performance of these two beetles and be used as a feed additive in rearing them.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.1
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• pp.1-12
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• 2013

The commercial rearing of polyphagous Indian tasar silkworm, Antheraea mylitta Drury being practiced on naturally grown primary food plants like Terminalia arjuna, (Arjun) Terminalia tomentosa (Asan), and Shorea robusta (Sal) available in the tropical forests of central India, at times, is seriously affected by the disease- Pebrine, caused by Nosema sp., a microsporidian pathogen. The present investigation on comparative larval, silk gland weight and also cocoon parameters in Pebrine-free and Pebrine-infected ecorace of tasar silkworm Antheraea mylitta Drury (Daba TV), illustrates the tasar silkworm larvae infected with pebrine disease causing heavy losses to the economy of the silk industry.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.113-116
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• 2001

Fifth instar larvae of the new bivoltine hybrid (CSR2 ${\times}$ CSR5) were reared under different temperature and humidity viz., $20^{\circ}C$ and 85 ${pm}$ 5% R.H (T1), $25^{\circ}C$ and 70 ${pm}$ 5% R.H (T2-Optimum), $30^{\circ}C$ and 80% ${pm}$ 5 R.H (T3) and $35^{\circ}C$and 50 ${pm}$ 5% R.H (T4). The cocoon yield, cocoon characters and disease incidence were studied in normal (non infectious source, i.e control) rearing as well as in 1% infectious source of rearing. The results indicated that V instar larval duration was prolonged and cocoon weight was improved in T1. ERR and shell ratio were significantly improved and disease incidence was minimised in T2. Further significant difference was observed among the treatments with regard to spread of diseases.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.203-208
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• 2003

Rearing temperature influences food consumption, conversion and cocoon production in silkworm Bombyx mori L. Young age $({1^st}to{3^rd} instar)$ worms of Pure Mysore, a multivoltine were reared at 26, 28, 30 and $32^{\circ}C$ followed by combinations of these temperature levels during late age $({4^th} and {5^th} instar)$. Food consumption, conversion, larval duration and growth for each instar were recorded. The influence of combinations of these temperature levels during rearing on survival and cocoon production was assessed. Food consumption increased with the temperature up to $4^th$ instar and decreased during $5^th$ instar. Temperature beyond $28^{\circ}C$ during young age followed by higher temperature ($30^{\circ}C$ and above) has shown deleterious effect on cocoon production. The paper discusses the rearing performance in relation to food intake and conversion under the tested temperature levels.