scholarly journals Influence of Planting Dates on the Population Density of the Main Insect Pests on Onion Crop in Kafr El-Shekh Region.

2017 ◽  
Vol 8 (8) ◽  
pp. 393-395
Author(s):  
S. Awadalla ◽  
A. Taman ◽  
A. Aboria
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Planting Dates

scholarly journals BIOLOGI DAN TRANSFORMASI BELALANG KEMBARA LOCUSTA MIGRATORIA MANILENSIS MEYEN (ORTHOPTERA: ACRIDIDAE) PADA BEBERAPA TINGKAT KEPADATAN POPULASI DI LABORATORIUM

2005 ◽  
Vol 5 (1) ◽  
pp. 24-31
Author(s):  
Hamim Sudarsono ◽  
Rosma Hasibuan ◽  
Damayanti Buchori
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Control Strategies ◽  
Locusta Migratoria ◽  
Feeding Activity ◽  
Laboratory Population ◽  
Migratory Locust ◽  
Green House ◽  
Cage Size ◽  
Locusta Migratoria Manilensis

Biology and Transformation of the Migratory Locust Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) at Several Laboratory Population Density Levels.  The migratory locust, Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) is one of insect pests in Indonesia that undergoes a unique polymorphic biology.  The locust develops a transformation phase which is triggered mainly by high population density.  Its recent outbreaks in several regions of Indonesia cause major concern and control strategies must be developed to strengthen control efforts in the future. Its unique polymorphic phenomenon, therefore, must be investigated thoroughly for the basis of management of the outbreak.  Due to its agility and its long range flying ability, the most realistic technique to study behavioral and morphological change of the locust is in controlled condition at a laboratory or a green house facility. The experiment was aimed to study effects of colony densities on the biology and transformation process of the migratory locust.  More specifically, the experiment was to study effects of population density on the feeding activity, mortality rate, and the ratio of F/C and E/F of the migratory locust L. migratoria manilensis.  The population densities were simulated in colonies at 2, 5, 10, 20, dan 30 couples per cage (cage size: 45x45x90 cm) reared in a green house. Results of the experiment show that, in general, higher densities of the migratory locust colonies tended to feed more rigorously than those of the less dense colonies.  The locust remained in solitary phase at the density of 2-5 couples per cage whereas the transient phase occured at the density of 10-20 couples per cage.  The colonies transformed to gregarious stage when their densities were 30 couples per cage or higher.  Mortality percentage tended to be higher at colonies with higher density, especially for the third instar of the migratory locust. 

scholarly journals Aedes albopictus (Skuse) susceptibility status to agrochemical-insecticides used in durian plantating systems in southern Thailand

2020 ◽  
Author(s):  
Sakda Ratisupakorn ◽  
Sokchan Lorn ◽  
Nsa Dada ◽  
Aran Ngampongsai ◽  
Pawit Chaivisit ◽  
...  
Keyword(s):  
Population Density ◽  
Aedes Albopictus ◽  
Insect Pests ◽  
Field Application ◽  
Insecticide Susceptibility ◽  
Future Studies ◽  
Lambda Cyhalothrin ◽  
Southern Thailand ◽  
Study Sites ◽  
Susceptibility Status

ABSTRACTHigh rates of dengue, chikungunya, and zika morbidity occur in southern Thailand. The intensive application of insecticides in orchards could impact not only agricultural insect pests, but also non-target insects, such as mosquitoes, or non-target beneficial insects. In this study, the population density and insecticide susceptibility of Aedes albopictus populations to field application concentrations of four agrochemical insecticides – cypermethrin, chlorpyrifos, carbaryl, and imidacloprid were examined. Mosquito eggs were collected from durian cultivation sites in five provinces in southern Thailand and hatched and allowed to develop to the adult stage. The study sites were categorized into three groups based on insecticide application; intensive-application of insecticides (IA), less-application of insecticides (LA), and no application of insecticides (NA). Twenty ovitraps were deployed for at least three consecutive days at each study site to collect mosquito eggs and to determine the Ae. albopictus population density then WHO tube assays being used to determine the susceptibility of adult mosquitoes to selected insecticides. This study represents the first report of the agrochemical insecticide susceptibility status of Ae. albopictus collected from durian orchards in southern Thailand. The study found that the populations of Ae. albopictus were susceptible to chlorpyrifos, but showed reduced mortality following exposure to lambda-cyhalothrin, carbaryl, and imidacloprid which is suggestive of the existence of resistance. These findings provide new insights into mosquito insecticide resistance focusing on Ae. albopictus populations and has important implications for mosquito and mosquito-borne disease control in Thailand as well as providing baseline data on which future studies can develop.

scholarly journals Effect of Silicon fertilization on two major insect pests of tomato under greenhouse conditions

2021 ◽  
Author(s):  
Aqeel Alyousuf ◽  
Dawood Hamid ◽  
Mohsen A. Desher ◽  
Amin Nikpay ◽  
Henk-Marten Laane
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Insect Pest ◽  
Tomato Leaf ◽  
Leaf Miner ◽  
Pest Species ◽  
Tomato Crop ◽  
Soil Drench ◽  
Tomato Leaf Miner ◽  
Acid Formulation

Abstract Tomato (Solanum lycopersicum L) is an important vegetable crop in Iraq. This horticultural crop is attacked by several insect pest species. Among them, the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and the tomato leaf miner Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) are the major threat of greenhouse tomatoes in Basrah province in south Iraq. The management of these pests is heavily based on application of chemical pesticides. Vast application of pesticides caused harmful damage to the environment, human health and may increasing the risk of pest resistance on insect populations. One of the promising strategies which are compatible with organic farming is application of silicon for enhancing plant vigor and resistance to pest damage on various agricultural crops. Due to these facts, the experiments have been carried out at Basrah University to evaluate the effects of silicon (Si) fertilization on tomato plants for reducing damage of these two major pests. Treatments comprised two type of Si applications (Soil drench treatment and foliar spraying) with four Si concentrations (0, 0.5, 1 and 2%) of AB Yellow ® silicic acid formulation. The population density of B. tabaci and T. absoluta were studied weekly during the growth season. The results clearly demonstrated that Silicon applications significantly decreased the population of immature of both whiteflies and tomato leaf miner on tomato crop in the greenhouse; Si-Foliar spraying was more effective in reducing the population density of these key pests compared to Si- soil drench application.

scholarly journals Changes in the population density of root-knot nematodes in fall cropping of oat with different planting dates

2011 ◽  
Vol 41 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Yasushi Tateishi ◽  
Masaaki Katsura ◽  
Hideaki Iwahori ◽  
Kenta Uesugi
Keyword(s):  
Population Density ◽  
Planting Dates ◽  
Root Knot Nematodes

Evaluation of row spacing and population density effects on grain sorghum over a range of northern Australian environments

1981 ◽  
Vol 21 (109) ◽  
pp. 210 ◽  
Author(s):  
GA Thomas ◽  
RJK Myers ◽  
MA Foale ◽  
AV French ◽  
B Hall ◽  
...  
Keyword(s):  
Population Density ◽  
Full Range ◽  
Moisture Stress ◽  
Grain Sorghum ◽  
Row Spacing ◽  
Root Pruning ◽  
Population Densities ◽  
Planting Dates ◽  
Wide Range ◽  
Growing Conditions

Fifteen experiments were conducted between 1976 and 1978 to determine the response of grain sorghum to row spacing and population density over a range of soil types, planting dates and seasonal conditions. One experiment was at Kununurra, Western Australia, and the rest were in southern and central Queensland. The trials virtually covered the full range of growing conditions likely to be experienced in the sorghum growing area. Narrow and standard single rows (0.33 m to 1.07 m spacings) yielded as well as or better than more widely spaced (1.50 to 4.27 m) single or twin rows (0.33 or 0.36 m apart) at equivalent population densities over a wide range of yield levels. Only at yield levels below 900 kg ha-l was there a trend for 2.00 or 2.13 m twin rows to outyield the 0.33 or 0.36 m single row spacing. Significant yield reductions resulted in a number of trials, at yield levels above 1600 kg ha-l, from the use of wide row spacings. Where there was severe water stress, grain yields were also reduced by high population densities (>150,000 plants ha-l), particularly at the 0.33 or 0.36 m row spacing. There was no evidence that response to row spacing differed between cultivars. In the one experiment where it was studied, root pruning had no effect on grain yield under conditions of ample moisture supply, but yield was reduced by root pruning of wide row sorghum (1.8 m spacing) under conditions of moisture stress.

scholarly journals Effect of sowing dates on the populations of three major insect pests and associated natural enemies throughout the growth stages of maize plants

2021 ◽  
Vol 90 (3 - Ahead of print) ◽  
pp. 130-144
Author(s):  
Hamdy H. Mahmoud ◽  
Soheir F. Abd El-Rahman ◽  
Magda H. Naroz ◽  
Sayeda S. Ahmed
Keyword(s):  
Natural Enemies ◽  
Insect Pests ◽  
Sowing Date ◽  
Growth Stages ◽  
Planting Dates ◽  
Formation Stage ◽  
Sowing Dates ◽  
Maize Varieties ◽  
Sesamia Cretica ◽  
Maize Plants

In Egypt, maize is an important crop that is attacked by various pests. In the present study, the effect of maize planting dates on the populations of insect pests and their natural enemies were investigated throughout the growth stages of maize plants. The maize planting dates were at the beginning of May, Jun, and July in the 2019 season and were repeated in the 2020 season. Samples were collected weekly to determine the populations of the insect pests, Limothrips cerealium (Haliday, 1836), Rhopalosiphum maidis (Fitch, 1856), and Sesamia cretica Lederer, 1857 and their natural predators. For the first sowing date, the infestation percentage of L. cerealium and S. cretica were most substantial, especially in the seedling and precorn formation stages. For the third sowing date, the number of R. maidis was most substantial, especially in the corn formation stage. Three predators were associated with these insect species; of these predators, Coccinella undecimpunctata (Linnaeus, 1758), Scymnus interruptus (Goeze, 1777), and Chrysoperla carnea (Stephens, 1836) were observed at the highest numbers during all sowing dates. A highly significant correlation existed between populations of S. interruptus and the three insects across the two seasons. Data suggest that the percentage of thrips, aphids, and stem borers infestations can be minimized by planting maize varieties in June.

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