Comparative study on host preference and damage potentiality of Red pumpkin beetle, Aulacophora foveicollis and Epilachna beetles, Epilachna dodecastigma

Experiments were carried out in the field and in the laboratory of the Department of Entomology, Bangladesh Agricultural University during the period from February to August, 2013. Three cucurbitaceous vegetables viz. bitter gourd, ridge gour d and snake gourd were used as test crops. Considering to percent leaf infestation and leaf area consumptions, red pumpkin beetle was found mostly harmful to snake gourd (22.62% and 8.84%, respectively) but least harmful to bitter gourd (3.00% and 1.25%, respectively). On the other hand, Epilachna beetle was found mostly damaging to bitter gourd (46.00% and 21.67% respectively) and least damaging to ridge gourd (11.20% and 5.00%, respectively). Similar to the field experiments, red pumpkin beetle consumed more leaf areas of snake gourd (up to 43.36%) and Epilachna beetle (both adult and grubs) consumed more leaf areas of bitter gourd (up to 91.46%) in the laboratory experiments. Bitter gourd (1.42%) and ridge gourd (0.78% to 41.27%) were least preferable to the red pumpkin beetle and Epilachna beetle, respectively.Res. Agric., Livest. Fish.3(3): 411-416, December 2016

Effect of bitter gourd (Cucurbitaceae) foliar constituents on development and reproduction of Epilachna dodecastigma (Coleoptera: Coccinellidae)

The influence of young, mature and senescent leaves of bitter gourd Momordica charantia L. (Cucurbitaceae) on the feeding, growth and reproduction of Epilachna dodecastigma (Weid.) (Coleoptera: Coccinellidae) were studied under laboratory conditions (27 ± 0.5 °C, 12 h light: 12 h dark photoperiod, 65 ± 5% RH). Larval developmental time of E. dodecastigma was longest on senescent leaves followed by young and mature leaves, whereas the pupal period was shortest on young and mature leaves. The longevity of females was generally higher than males. Male and female longevity were highest on mature leaves and lowest on senescent leaves. Fecundity was highest on mature leaves followed by young and senescent leaves. The growth and development of E. dodecastigma were related with nutrient and phenol content of three types of bitter gourd leaves. Carbohydrate content was higher in young and mature leaves, whereas protein, nitrogen, amino acid and lipid content were in greater quantities in mature leaves followed by young and senescent leaves. Phenol content was greatest in senescent leaves and least in mature leaves. Higher level of carbohydrates, proteins, lipids, nitrogen and amino acids including water content and lower phenol content of mature leaves had influenced higher growth rate and fecundity of E. dodecastigma.

Host Preference of Epilachna Beetle, Epilachna dodecastigma (Wied.) among Cucurbitaceous Vegetables

A series of experiments were carried out at the field and laboratory of the Department of Entomology, Bangladesh Agricultural University to determine the host preference of Epilachna beetle, Epilachna dodecastigma (Wied.) among four cucurbitaceous crops viz. cucumber, bottle Gourd, sweet Gourd and bitter Gourd. Three varieties of each crop were tested. Data on insect incidence, infestation, food consumption and fecundity of E. dodecastigma were collected. The highest number of Epilachna beetle was recorded on cucumber and the lowest was on bottle Gourd both in open field and in net cage condition. Among the varieties, the highest insect incidence was recorded on Sitol Sosa and the lowest was on BARI Lau-4 both in open field and in net cage. The highest leaf and twig infestation was found on cucumber crop and its’ Sitol Sosa variety, while the lowest was on bottle Gourd crop and its' BARI Lau-4 variety in both open field and in net cage. The Epilachna beetle showed the similar host preference in case of daily food consumption and oviposition rate both in net cage and laboratory condition. Thus, considering the insect incidence, infestation, food consumption and fecundity, the crop cucumber and the tested Sitol Sosa variety appeared to be the most preferred host for Epilachna beetle.Int J Appl Sci Biotechnol, Vol 3(2): 352-358 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12809

Attraction of Epilachna dodecastigma (Coleoptera: Coccinellidae) to Momordica charantia (Cucurbitaceae) leaf volatiles

Epilachna dodecastigma (Wiedemann) (Coleoptera: Coccinellidae) is an important herbivorous pest of bitter gourd, Momordica charantia Linnaeus (Cucurbitaceae) plant in India and Bangladesh. Volatiles were collected from undamaged bitter gourd plants, and from plants 24 and 120 hours following the initiation of continuous adult female feeding damage, and subsequently identified and quantified by gas chromatography mass spectrometry and gas chromatography flame ionisation detector analyses. Of the 24 volatiles identified in the study, 22 were present in all three treatments (undamaged plants, 24 hours after feeding, and 120 hours after feeding), and all plants significantly increased emissions of these compounds following insect attack. In all plants, the compound 1-tridecanol was the most abundant, followed by phytol. Only two compounds were unique to insect damaged plants: methyl palmitate was characteristic of insect damaged plants, while nerolidol was only detected from plants 120 hours following insect attack, however neither of these insect-damage specific volatiles, when tested individually, elicited attraction in Y-shaped glass tube olfactometer bioassays. Epilachna dodecastigma showed significant preference for the whole volatile blends from insect damaged plants compared with whole volatile blends from undamaged plants. Further, the insect elicited attraction to three individual synthetic compounds: geraniol, 1-tridecanol, and phytol, which had significantly higher emissions from insect damaged leaves compared with those from undamaged plants.

Effect of Temperature on the Bahaviour of Epilachna Beetle (Epilachna dodecastigma Wied.) among Different Brinjal Varieties

An experiment was carried out to study the effect of temperature on biology, oviposition and feeding behaviour as well as host preference of Epilachna beetle, Epilachna dodecastigma (Wied.) on eight varieties of brinjal, Solanum melongena Linn. from November, 2009 to June, 2010 maintaining controlled temperatures of 15ºC, 25ºC and 30ºC using an incubator in the Department of Entomology, BAU, Mymensingh. Temperature has a profound influence on the oviposition and food consumption of Epilachna beetle. In incubator at 15oC, 25oC and 30oC temperature, larval daily average food consumption (mm2) among eight host plant varieties of S. melongena was the highest on Thamba and the lowest on Bijoy, whereas adults daily mean food consumption at three temperature regimes was the highest on Thamba and the lowest on BAU-2 at 15oC and 25oC temperature and at 30oC temperature the lowest recorded on Bijoy. At 25oC temperature, the highest oviposition was recorded on Thamba and the lowest found on Jhumki. Similarly at 15oC and 30oC temperature, the highest oviposition was also observed on Thamba and the lowest on Bijoy. Thus, the varieties namely Thamba, ISD 006 and Kazla appeared to be preferable hosts, whereas Bijoy, BAU-2 and Jhumki seemed to less preferable. The results revealed that temperature had direct effect on the behaviour and 25°C temperature was congenial to both fecundity and food consumption of the Epilachna beetle. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11572 J. Environ. Sci. & Natural Resources, 5(1): 167 - 172, 2012