| dc.contributor.advisor | Professor Dr. Md. Alamgir Hossain | |
| dc.contributor.author | RAHMAN, MD. HABIBUR | |
| dc.date.accessioned | 2022-04-19T09:20:26Z | |
| dc.date.available | 2022-04-19T09:20:26Z | |
| dc.date.issued | 2016-12 | |
| dc.identifier.uri | http://localhost:8080/xmlui/handle/123456789/251 | |
| dc.description | Onion (Allium cepa L.), the kitchen of queen is an important spice crop in Bangladesh.
In Bangladesh, it ranks first in production (989000 MT) and second in area (125101 ha)
among the spices and it covers almost 36% of the total areas under spices (BBS, 2013).
The mean yield of onion in Bangladesh is very low (4 t/ha) compared to world average
of 18.21 t/ha (FAO, 2004). During winter, it is widely cultivated all over the country. Its
cultivation is concentrated in the greater districts of Faridpur, Pabna, Rajshahi, Jessor,
Mymensingh, Comilla and Rangpur. Although production of onion is increasing day by
day, but in a land hungry country like Bangladesh, it may not be possible to meet the
domestic demand due to increase in population. There is an acute shortage of onion in
relation to its requirement. Every year, Bangladesh has to import a big amount of onion
from neighbouring and other countries to meet up its demand. The high demand of
onion can only be met by increasing its production vertically. Farm level yield of onion
is very low compared to their recommended yield. | en_US |
| dc.description.abstract | The experiment was conducted to study the incidence of onion thrips, Thrips tabaci
(Lindeman) in field conditions and mortality also tested using three different solvent
(acetone, petroleum benzene and distilled water) extracts of neem leaf powder in the
laboratory of the Department of Entomology, HSTU, Dinajpur during the period from
November, 2015 to April, 2016. Results showed that the highest number of thrips was
observed at the end of March, 2016 while the lowest was 3.93 due to heavily rainfall on
29 March, 2016. The average number of nymphs per plant was 4.91 when plant height
was 39.49 cm then the number of nymphs increased up to 20.37 when the plant height
was 42.78 cm. The maximum number of thrips (20.37) was observed at the end of
March, 2016 when the mean number of leaves per plant was 4.11. The number of thrips
per plant was negatively correlated with leaves per plant and plant height. Weather
parameters (temperature, humidity and rainfall) had great influence on incidence of onion
thrips population. In case of temperature, thrips population gradually increased with
increasing average temperature at a certain level. On the other hand, thrips population
decreased with increasing relative humidity and rainfall (cm). Among the tested extracts,
acetone extract of neem leaf powder provided the highest mortality (33.67%) while the
extract with distilled water caused the lowest mortality (12.33%). In case of control
treatment, no mortality of thrips was found. The lowest LDso values of acetone extract of
neem leaf powder at 1, 2, 3, 4 and 5 HAT indicated that acetone extract possessed the
highest toxic effects. Acetone extract was highly toxic to nymphs of onion thrips and
which provided 100% mortality within 5 hours after exposure. The LT so (h) values of
acetone extract (1.56) provided best performance among the tested extract. It is revealed
from the results that plant height, number of leaves and weather parameters have
influence on incidence of onion thrips population. It is also revealed that acetone extract
of neem leaf powder performed well to check the T. tabaci infestation. | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR. | en_US |
| dc.subject | Cultural manipulation | en_US |
| dc.subject | Location of the experimental plot | en_US |
| dc.subject | Seeds used for experiment | en_US |
| dc.title | INCIDENCE AND CONTROL OF THRIPS TABACI (THYSANOPTERA: THRIPIDAE) ON ONION USING NEEM LEAF EXTRACTS | en_US |
| dc.type | Thesis | en_US |
