South Pacific Stusy Vol. 18, No. 2, 1998

Effects of Optimum Dosages of Nitrogen, Potassium, Calcium andCopper on Silkworm, Bombyx mori L. Development and Silk Yield

Muhammad ASHFAQ 1), Nisar AHMAD 2), and Amjad ALI 3)

Abstract

The role of mineral nutrients supplemented by mulberry leaves, after feeding to the silkworm larvae Bombyx
mori was determined following completely randomized design with 6 treatments having three repeats. The
differences were found to be significant among treatments. The treatment T5 i.e., 0.2 ％ N ＋ 0.3 ％ K ＋ 0.1％
Ca ＋ 0.05％ Cu gave maximum food consumption (55.82 g 10 larvae) and coefficient of utilization (65.71％)
on cumulative basis, maximum larval body weight (62.42 g 10 larvae), body length (7.667 cm larva) and cocoon
yield with (1.487 g cocoon) and without pupa (0.2967 g cocoon)
Key words: Pakistan, mineral nutrients, silkworm, silk yield

Introduction
Sericulture is one of the major labour intensive cottage industry, capable of significant
contribution towards easing the problems of unemployment and improving the socioeconomic status of the rural masses. There are about 5,500 silk looms in Pakistan andalmost 62,000 people engaged in silkworm rearing, 3,000 in silk trade and reeling and morethan 10,000 in weaving silk cotton (AHMAD and MUZAFFAR, 1987:6). Silkworm nutritionists have always been searching for better food by supplementing the mulberry leaves withdifferent
nutrients.
Variousmineralsviz.,
0.2％
N(HAQandSALEEM, 1985:4 & MAHMOOD, 1989:76), 0.3％ K ＋ 0.2％ N (JAVAID, 1991:77), 0.1 Ca(MAQBOOL, 1991:79), 0.2％ N ＋ 0.1％ Ca ＋ 0.1％ K (ISHTIAQ and AKHTAR, 1992:3),
0.2％ N ＋ 0.1％ P ＋ 0.1％ K (AHMAD, 1993:76), 0.5％ Ca ＋ 0.1％ N(HUSSAIN, 1993:75) reported to have good influence on silkworm survival and yield.
Keeping the attempts of earlier workers in view, the present project was planned to determine the effect of optimum dosages of important nutrients in different combinations on thedevelopment of silkworm and on the silk yield.

1) Ph.D. Agri. Entomology, Professor of Entomology, Univ. Agric., Faisalabad.
2) M.Sc. Std., Dep. Entomol., Univ. Agric., Faisalabad.
3) Ph.D. Agri. Entomology, Assistant Research, Officer, Entomol. Sec., Ayub Agric. Res. Ins., Faisalabad.

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South Pacific Study Vol. 18, No. 2, 1998

Materials and Methods
The eggs of silkworm, Bombyx mori L. were purchased from Forest Department,
Faisalabad (Pakistan) in the month of February, 1995, placed in an incubator run at 24-2
7℃ and 70-80％ R.H. for hatching. Six treatments viz., mulberry leaves dipped in distilledwater as a control (T0), in 0.2％ N ＋ 0.3％ K and 0.1％ Ca (T1), in 0.2％ N ＋ 0.3％
K and 0.05％ Cu (T2), in 0.3％ K ＋ 0.1％ Ca and 0.05％ Cu (T3), in 0.2％ N ＋ 0.1％
Ca and 0.05％ Cu (T4), in 0.2％ N ＋ 0.3％ K, 0.1％ Ca and in 0.05％ Cu (T5) were
designed in three repeats under CRD. The newly hatched 1st and 2nd instar larvae were fed
on chopped mulberry leaves while full grown fresh leaves dipped in combinations ofdifferent minerals were offered to the later instars. Data on food consumption, coefficientof utilization, larval weight along with larval length and cocoon weight with and without
pupa were recorded. The data were analysed statistically with IBM Compatible Computer
using Mstat Package.

Results and Discussion
The results (Table 1) on cumulative food consumption indicates that maximum preference of the silkworm larvae to mulberry leaves was observed in T5, where most optimumcombination of minerals was used, (i.e., 0.2％ N ＋ 0.3％ K, 0.1％ Ca and 0.05％ Cu).
Whereas, minimum food consumption was observed in T0, where mulberry leaves weredipped in distilled water. A number of research workers such as
MAHMOOD (1989:76) and ISHTIAQ and AKHTAR (1982:3), have reported better foodconsumption from diet containing optimum mineral nutrients.
The food converted into body matter during the entire larval life confirms that the individuals, which were fed the mulberry leaves impregnated with a combination of optimum
dozes of mineral nutrients (T5) were not only consumed to the maximum but were also
converted maximum of it into body matter. The conclusions drawn byJAVAID (1991:77), ISHTIAQ and AKHTAR (1992:3) and HUSSAIN (1993:75) for bettercoefficient of utilization after feeding the silkworm larvae on artificial diet or mineral
supplemented mulberry leaves are in confirmation to the present findings.
Body weight and body length are two important parameters of the life of silkworm andare ultimately dependent upon better food quality, rate of consumption and coefficient ofutilization. During the present investigation, it has been observed that in case of maximum
food consumption and coefficient of utilization (T5) the performance of the silkworm
larvae in terms of body weight and length was also found maximum and it was only due tobetter food. The body weight during 5th instar thus recorded to be 62.47 g 10 larvae
whereas, body length during 5th instar was 7.667 cm larvae. These findings are in conformity with those of MAHMOOD (1989:76) who also recorded better body weight as well as

ASHFAQ: Effects of Optimum Dosages of Nitrogen, Potassium, Calcium and Copper on Silkworm, Bombyx mori L. Development and Silk Yield

49

length after feeding mineral supplemented mulberry leaves.
The net outcome of the present studies is reflected in the form of better cocoon yield
which again confirmed the outcome of previous workers like MAQBOOL (1991:79) and J
AVAID (1991:77) who got the similar results after feeding the mulberry leaves impregnatedwith various minerals individually.
Keeping all the results presented here in view, it can be safely said that the individuals
fed in T5 resulted not only in better food consumption, coefficient of utilization, and larval
development but also produced heavier cocoons.
Table 1. Effect of minerals on the silkworm,
Bombyx mori L. development and cocoon yield
Treatments

Consumption Coefficient
g／10 larvae ofutilization(％)

5th instar
Body lengthlarval
cm／larva
body weight／
10 larvae(g)Fresh green
cocoonweightwith pupa(g)

Cocoonweight
without
pupa
(g)

T0

40.19 b49.72 c49.65 b6.81 b1.265 e0.1747 c

T1

53.89 a61.84 b61.35 a7.59 a1.377 d0.2333 bT2

54.33 a64.37 ab61.22 a7.61 a1.442 b0.2933 aT3

55.39 a63.00 ab62.41 a7.57 a1.380 d0.2300 b

T4

55.60 a63.25 ab62.44 a7.62 a1.407 c0.2300 bT555.82 a

65.71 a62.47 a7.67 a1.487 a0.2967 a

Means sharing similar letters are not significantly different by DMR Test at P ＝ 0.05.
Where;
T0 ＝ mulberry leaves dipped in distilled water as check,
T1 ＝ mulberry leaves dipped in 0.2％ N ＋ 0.3％ K and 0.1％ Ca,
T2 ＝ mulberry leaves dipped in 0.2％ N ＋ 0.3％ K and 0.05％ Cu,
T3 ＝ mulberry leaves dipped in 0.3％ K ＋ 0.1％ Ca and 0.05％ Cu,
T4 ＝ mulberry leaves dipped in 0.2％ N ＋ 0.1％ Ca and 0.05％ Cu,
T5 ＝ mulberry leaves dipped in 0.2％ N ＋ 0.3％ K, 0.1％ Ca and 0.05％ Cu.

References
AHMAD, R. and MUZAFFAR, N. 1987. Rearing of silkworm (in Urdu). NARC, Islamabad.
1-6 pp.
AHMAD, Z. 1993. Effect of nitrogen, phosphorus and potassium treated mulberry leaves onlarval development and silk yield of Bombyx mori L. M.Sc. Thesis, Dep. Agric.
Entomol., Univ. Agric., Faisalabad.
HAQ, M. and SALEEM, M. 1985. Quantitative and qualitative feeding effects on silkworm,Bombyx mori L. Jour. Agric. Res., 23(1):43-46.
HUSSAIN, A. 1993. Impact of feeding calcium and nitrogen treated mulberry leaves on the50

South Pacific Study Vol. 18, No. 2, 1998

development of silkworm, Bombyx mori L. and silk yield. M.Sc.(Hons.) Thesis, Dep.
Agric. Entomol., Univ. Agric., Faisalabad.
ISHTIAQ, A. and AKHTAR, M. 1992. Effect of feeding nitrogen, calcium and potassium
treated mulberry leaves, on the larval development and silk yield of Bombyx mori L. Pak.
Entomol., 14 (1-2):74-76.
JAVAID, M. A. 1991. Effect of treated mulberry leaves with mineral supplements (N, K) on
the development of silkworm and silk yield. M.Sc. (Hons) Thesis, Dep. Agric. Entomol.,Univ. Agric., Faisalabad.
MAHMOOD, R. 1989. Effect of nitrogen on the larval development and silk yield of Bombyx
mori L. in relation to its nutritional requirement. M.Sc. (Hons) Thesis, Dep. Agri.
Entomol., Univ., Faisalabad, Pakistan.
MAQBOOL, S. 1991. Effect of feeding Calcium and Nitrogen treated mulberry leaves onlarvae development and silk yield of Bombyx mori L. M.Sc. (Hons). Dep. Entomol.,Univ. Agric., Faisalabad, Pakistan.
(Accepted 8 December 1997)