FACTORS INFLUENCING INFESTATION AND INJURY OF RUTABAGAS BY ROOT MAGGOTS (DIPTERA:ANTHOMYIIDAE) IN PRINCE EDWARD ISLAND. I. FIELD STUDIES

1958 ◽  
Vol 38 (2) ◽  
pp. 188-198 ◽  
Author(s):  
D. C. Read

Examinations of more than 100 rutabaga fields per year, from 1951 to 1955, showed that Hylemya brassicae (Bouché) was the only species of root maggot that injured rutabagas in Prince Edward Island. H. liturata (Mg.) (= H. trichodactyla (Rond.)), H. cilicrura (Rond.), and Muscina stabulans (Fall.) were associated with H. brassicae but did not injure the roots. H. brassicae flies [note Whitcomb (12) for illustrations] began to emerge from overwintered puparia early in June in sandy soil areas and late in July in clay loam areas. Heavy texture and high moisture content of soils were closely correlated with the delay in emergence. The flies laid their eggs near rutabaga plants, usually in crevices in the soil, and upon hatching the larvae entered and fed on the roots. Larvae generally entered the roots at a depth of one inch or more below the surface of the soil. In general, early-planted rutabagas in sandy soil areas and late plantings in clay loam areas were severely damaged by larvae of H. brassicae, whereas late plantings in sandy areas and early plantings in clay loam areas were lightly infested. However, in the sandy soil areas where all of the rutabaga crops were harvested early in August damage was relatively light. Also, fields isolated by other rutabaga fields from sources of infestation such as storage bins and infested rutabaga crops, of either the current or the previous season, were usually slightly damaged. Use of barnyard manure increased H. brassicae infestations early in the season but did not significantly influence the damage caused during the whole growing season.

1960 ◽  
Vol 40 (4) ◽  
pp. 721-728
Author(s):  
D. C. Read

Experiments in 1958 and 1959 with pre-planting soil treatments of insecticides, applied in a 5-inch band [Formula: see text] below the seed in ridges of soil, snowed that heptachlor, aldrin and chlordane, each at 5 pounds toxicant per acre, gave 70 to 90 per cent reduction in root maggot damage in cruciferous crops in Prince Edward Island. Each of these insecticides gave better control of the second than of the first generation of root maggots. Nematocide 18,133, at 5 and at 10 pounds per acre gave complete control throughout the growing season and also gave the highest yield. Thimet at 5 and at 10 pounds gave better control than the chlorinated hydrocarbons; parathion and Guthion, at the same rates, gave better control of the first generation but not as effective control thereafter. Korlan at 6 pounds gave fair control of the first generation but was ineffective thereafter. Ethion, Trithion, Di-syston and Diazinon, each at 5 and at 10 pounds, and Co-Ral and Dylox at 5 pounds were ineffective in controlling root maggot injury. Diazinon was highly phytotoxic; none of the other insecticides showed any phytotoxicity.


1986 ◽  
Vol 26 (4) ◽  
pp. 431 ◽  
Author(s):  
MJ Barbetti

In field studies we monitored the effects of time of season, trash and fungicides on the populations of fungi associated with leaves and petioles of newly sown subterranean clover, particularly in relation to the development of disease symptoms. These effects were compared with the fungal population changes occurring in a nearby established subterranean clover pasture. A range of fungi, notably Leptosphaerulina trifolii, Phoma medicaginis and Stemphylium globuliferum, were found to colonise subterranean clover cotyledons, leaves and petioles readily throughout the growing season from as early as 1 week after emergence. The incidence of L. trifolii and S. globuliferum was reasonably consistent throughout the growing season. Alternaria spp., Cladosporium spp., Myrothecium verrucaria, P. medicaginis and Trichoderma spp. were more prevalent later in the season. Fusarium avenaceum and other Fusarium spp. were more prevalent early in the season, while Pithomyces chatarum and S. botryosum were more prevalent midseason. The fungi isolated showed no ability, under the conditions of this investigation, to cause disease, and there was no correlation between fungi isolated and disease symptoms observed. The incidence of several fungi, especially L. trifolii and P. medicaginis, was greatly increased by the presence of trash from the previous season but was greatly decreased by regular applications of fungicide.


2008 ◽  
Vol 22 (4) ◽  
pp. 565-570 ◽  
Author(s):  
S.D. Willingham ◽  
N.R. Falkenberg ◽  
G.N. McCauley ◽  
J.M. Chandler

Clomazone was labeled for rice in 2001; however, that label excluded its use on coarse- (light) textured soils, including sand, loamy sand, and sandy loam with less than 1% organic matter due to rice injury. Field studies conducted in 2005, 2006, and 2007 evaluated weed control and tolerance of rice to early postemergence (EPOST) applications of clomazone alone and tank mixed with other herbicides on sandy loam and clay loam soils. At 42 d after treatment (DAT), broadleaf signalgrass (BRAPP) and barnyardgrass (ECHCG) control was > 86%. At 14 DAT, rice injury was greatest (13%) from clomazone applied preemergence (PRE) at 0.44 kg ai/ha on sandy soil. Annual sedge (CYPCP) control was > 78% on sandy loam soils at 14 DAT, but increased to > 90% by 42 DAT. On clay loam soils, CYPCP control at 42 DAT ranged from 60 to 76% from clomazone alone or tank mixed with cyhalofop or fenoxaprop. All other tank mixes provided > 80% control. Hemp sesbania (SEBEX) control was > 80% from all tank mixes. Clomazone alone provided < 77% control. Data suggest that clomazone can be used EPOST in combination with other herbicides without causing significant rice injury on sandy loam soils in Texas.


1964 ◽  
Vol 96 (1-2) ◽  
pp. 136-137 ◽  
Author(s):  
D. C. Read

Application of 5 Ibs. toxicant Ileptachlor or aldrin per acre placed in a 4- to 5-inch hand about 1½ inches below the surface of the soil in a ridged seeding drill have controlled infestations of the cabbage root maggot, Hylemya brassicae (Bouche) in cabbage and rutabagas for eight consecutive years on one farm in Prince Edward Island without detectable indications of resktance. The insecticide is so placed in the soil as to be most concentrated against the young root maggot larvae and least concentrated against the following predators and parasites: Coenosia tigrina (Fall.) and Scatophaga stercoraria. (L.), which attack and destroy H. brassicae flies in flight, on the soil surface, or on plant foliage; various species of Carabid beetles which destroy H. brassicae eggs at or near the soil surface, Trybliographa rapae (L.), the larvae of which parasitize and destroy H. brassicae larvae in the plant roots; and Aleochara bilineata (Gyll.), with adults destroying H. brassicae eggs or young larvae near the soil surface, and larvae in the plant roots, and the larvae parasitising H. brassicae puparia and destroying the pupae. Records of field observations, supplemented with data obtained on green-house determinations of the potential reproduction of both predators and host, indicate that any one of these predators could theoretically eliminate the pest population from an area in two to three generations. They do not eliminate or even give apparent economic control of the pest because a) the aerial attackers do not find and destroy adults of the pest before many eggs are deposited in the soil; b) many eggs are hidden in the soil by wind and rain and thus protected from discovery by predators; and c) larval and puparial parasites attack after the pest has injured the crop.


2017 ◽  
Vol 12 (3) ◽  
pp. 400 ◽  
Author(s):  
Valdiney Cambuy Siqueira ◽  
Flávio Meira Borém ◽  
Guilherme Euripedes Alves ◽  
Eder Pedroza Isquierdo ◽  
Afonso Celso Ferreira Pinto ◽  
...  

Objetivou-se, com o presente trabalho, propor um novo método de processamento e secagem, assim como avaliar o comportamento dos grãos submetidos a este processo, por meio da taxa de redução de água e do ajuste de diferentes modelos matemáticos aos dados experimentais da secagem. Os frutos colhidos no estágio maduro foram divididos em três lotes. O primeiro foi seco continuamente à temperatura de 40±1 °C. O segundo consiste na secagem do café natural até os teores de água de 0,56±0,02, 0,41±0,02, 0,28±0,02 e 0,20±0,02 decimal (base seca, b.s.), seguido de beneficiamento e secagem contínua nas temperaturas de 35±1 ºC e 40±1 ºC. O terceiro lote correspondeu à secagem contínua do café descascado e desmucilado na temperatura de 40±1 °C. Em todos os lotes, a secagem foi encerrada quando os grãos atingiram o teor de água de 0,12±0,05 (b.s.). Aos dados experimentais da secagem foram ajustados dez modelos matemáticos utilizados para representação da secagem dos produtos agrícolas. Além da representação da cinética de secagem foi avaliada a taxa de redução de água dos grãos. Conclui-se que a taxa de redução de água é maior para a temperatura de secagem de 40±1 °C, especialmente para maiores teores de água. O tempo total de secagem do café beneficiado com alto teor de água é expressivamente reduzido, quando comparado ao tempo de secagem completa do café natural. O modelo de Midilli descreve satisfatoriamente a cinética de secagem do café beneficiado.


2014 ◽  
Vol 124 ◽  
pp. 267-274 ◽  
Author(s):  
Seung-Hyun Moon ◽  
In-Soo Ryu ◽  
Seung-Jae Lee ◽  
Tae-In Ohm

Author(s):  
Ayalew Demissew ◽  
Ayenew Meresa ◽  
Keber Temesgen

Onion (Allium cepa L.) is a strong-flavoured vegetable consumed in different ways and its distinctive flavor or simply pungency. Onion has also important natural compounds effective for medical functions. Its importance is directly related with high content of high organosulphur compounds. Shelf life of fresh onion bulb is short enough due to the presence of high moisture content where postharvest loss of onion bulb reaches up to 50% in the production season. Consequentially Onion bulb had extreme variable market price during production and off season which affect both growers and consumers. So in this study the nutritional and volatile components of different drying methods of onion were evaluated. Effect of different drying method on protein, carbohydrate, total sugar, fat, pyurvic acid, ascorbic acid, total phenol, total flovonol, rehydration ratio, colour and sensory properties of onion slice were evaluated and found insignificant at (P &lt; 0.05) for microwave and modified direct solar dryer. But oven drying method had significant effect on onion bulb quality attributes at (P &lt; 0.05) than other two drying methods.


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