Control of experimental Phytophthora cinnamomi stem infections of Rhododendron, Leucadendron and Eucalyptus by dimethomorph, fosetyl-Al and metalaxyl

1990 ◽  
Vol 30 (1) ◽  
pp. 139 ◽  
Author(s):  
GC Marks ◽  
IW Smith
Keyword(s):  
Phytophthora Cinnamomi ◽  
Lesion Development ◽  
Potassium Dihydrogen ◽  
Foliar Sprays ◽  
Soil Drench ◽  
Test Conditions ◽  
Lesion Extension

The efficacy of dimethomorph, (E,Z)-4-[3- (4-chloropheny1)-3-(3,4-dimethoxypheny1)-1 -acryloyl] morpholine, in controlling Phytoplzthora cinnanionii stem infections of Rhododendron, Leucadendron and Eucalyptus was compared with that of fosetyl-Al, metalaxyl and phosphonate (potassium dihydrogen phosphonate) in a phytotron and greenhouse. The plants were inoculated on the stem and the effect of the fungicides applied either as foliar sprays or root drenches on lesion development was measured. The results showed that dimethomorph inhibited lesion extension when applied as a soil drench at rates of 0.6 and 1.2 mg a.i./mL. When used as a soil drench dimethomorph was about as effective as fosetyl-A1 and somewhat less effective than metalaxyl. When applied as foliar sprays, dimethomorph was ineffective and phosphonate was markedly superior to fosetyl-Al. Single applications of the fungicides tested were not able to kill P. cinnanzonzi in established infections within the duration of the experiment and under the test conditions which strongly favoured the fungus. Dimethomorph was slightly phytotoxic to Eucalyptus sieberi at dosages of 1.2 mg a.i./mL.

Development of Lesions Caused by Phytophthora cinnamomi in the Secondary Phloem of Eucalyptus marginata

1983 ◽  
Vol 31 (2) ◽  
pp. 197 ◽  
Author(s):  
JT Tippett ◽  
SR Shea ◽  
TC Hill ◽  
BL Shearer
Keyword(s):  
Phytophthora Cinnamomi ◽  
Wall Material ◽  
Secondary Phloem ◽  
Phloem Tissue ◽  
Lesion Development ◽  
Eucalyptus Marginata ◽  
Parenchyma Cells ◽  
Lesion Extension ◽  
Sieve Tubes ◽  
Intermittent Activity

Phytophthora cinnamomi Rands invaded the secondary phloem of inoculated roots and stems of Eucalyptus marginata Donn. ex Sm. For 12 months after inoculation, lesion development was followed in coppice stems. As lesions extended, the phloem or inner bark became discoloured due to the accumulation and oxidation of polyphenols. Starch also was deposited in the necrotic phloem. The primary wall material of sieve tubes and associated parenchyma was hydrolysed but fibres were unaffected. Fungal spread was most rapid in the outer phloem tissue where cells were loosely packed and characterized by many expanded parenchyma cells. Fungal invasion of the inner phloem resulted in cambial kill. Roots were not girdled by the fungus in the first 12 months after inoculation, as they resisted tangential spread of the fungus more effectively than coppice stems. Lesions were contained once necrophylactic (wound) periderms formed in the bark. Although the necrophylactic periderm restricted fungal activity during winter and spring, the fungus did 'break-out' in summer and invade new areas of phloem in 50% of the inoculated roots and stems. Summer lesion extension was usually associated with kino production: a series of kino veins reflected the intermittent activity of the fungus. Once the characteristics of typical lesions were recognized, interpretation of root lesions resulting from natural infections was possible.

Control of Phytophthora canker with phosphonate in artificially inoculated almond and cherry trees

1990 ◽  
Vol 30 (3) ◽  
pp. 413 ◽  
Author(s):  
TJ Wicks ◽  
B Hall
Keyword(s):  
Effective Treatment ◽  
Foliar Spray ◽  
Inhibitory Effect ◽  
Mature Trees ◽  
Foliar Sprays ◽  
Soil Drench ◽  
Trunk Injection ◽  
Cherry Trees

Phosphonate (H3P03; as FOLI-R-FOS 200) applied as either a soil drench, foliar spray or trunk injection before infection inhibited the development of cankers in almond and cherry trees inoculated with Phytophthora cambivora. Phosphonate applied to the foliage in autumn and spring at rates up to 2 g a.i./L was the most effective treatment. Soil drenches up to 10 g a.i./L were also effective, particularly on young trees. Trunk injections completely inhibited the development of P. cambivora in many cases, but due to a possible phytotoxic reaction, the treatment was most suited for mature trees. Foliar sprays of phosphonate are likely to be most practical treatment as these could be applied with other foliar treatments. The inhibitory effect of phosphonate on canker growth persisted for at least 48 weeks after treatment, irrespective of the method of application.

scholarly journals Apple Tree Vigor Influences Flowering and Dry Weight after Paclobutrazol Application

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 933-935 ◽  
Author(s):  
Laura J. Lehman ◽  
Eric Young ◽  
C.R. Unrath
Keyword(s):  
Weight Gain ◽  
Malus Domestica ◽  
Apple Tree ◽  
Dry Weight ◽  
Fibrous Root ◽  
Foliar Sprays ◽  
Soil Drench ◽  
Root Dry Weight

Spur-type or nonspur `Delicious' apple scions on either Malus domestica Borkh. (seedling) or M.26 rootstocks received paclobutrazol foliar sprays in one or two `consecutive years or a soil drench in the year of planting. For each scion, total shoot, root shank, and tree dry weights measured in the 3rd year after planting were suppressed by all treatments. Trees on M.26 put less dry weight into rootstock wood after foliar sprays, but trees on seedling were not similarly affected. No treatment influenced fibrous root dry weight of the spur-type scion on seedling, while all treatments suppressed dry-weight gain of the same scion on M.26. All trees had higher root: shoot ratios and blossom densities 3 years after the soil drench and several had higher ratios after foliar sprays. Chemical name used: ß-[(4-chlorophenyl)methyl] (l,l-dimethylethyl)-l-H-1,2,4-triazole-l-ethanol (paclobutrazol, PB).

Fungicidal control in pineapple and avocado of diseases caused by Phytophthora cinnamomi

1980 ◽  
Vol 20 (102) ◽  
pp. 119 ◽  
Author(s):  
RN Allen ◽  
KG Pegg ◽  
LI Forsberg ◽  
DJ Firth
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Soil Surface ◽  
Soil Drench ◽  
Old Trees ◽  
Better Than

Root and heart rot diseases of pineapples and root rot of avocado caused by P. cinnamomi were controlled with fungicides. In pineapples, treatments were applied at planting and again after one and two months. Ridomil (0.8 kg a.i. ha-1) and Aliette (8 kg a.i. ha-1) controlled P. cinnamomi better than the standard Difolatan treatment (11 kg a.i. ha-1). In avocado nursery plants, Ridomil mixed with the soil before planting (1 g a.i. per 10 l soil) or drenched onto the soil surface around established plants (1 g a.i, per 10 1 container) controlled root rot for at least four months after treatment. Two applications of Ridomil, applied at a rate of 5 g a.i. m-2 as a soil drench beneath the canopy of 7 year old trees affected by root rot, controlled P. cinnamomi without affecting its biological antagonists and permitted trees to recover over a 12-month period.

scholarly journals Control of Phytophthora Root Rot of Rhododendron chapmanii A. Gray with Subdue

1989 ◽  
Vol 7 (2) ◽  
pp. 73-75
Author(s):  
D. M. Benson ◽  
Frank A. Blazich
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Rooted Cuttings ◽  
Phytophthora Root Rot ◽  
Soil Drench ◽  
The One

Abstract Rooted cuttings of Chapman's rhododendron (Rhododendron chapmanii) in soilless medium were challenged with inoculum of the soi1borne fungus, Phytophthora cinnamomi (Rands). A portion of the plants received a soil drench of Subdue 2EC (metalaxyl) at 0.16 ml/L (2.0 oz/100 gal) at 2 month intervals. Chapman's rhododendron was highly susceptible to P. cinnamomi, but five of six plants treated with Subdue did not develop symptoms of Phytophthora root rot. In the one plant which developed root rot symptoms, P. cinnamomi was recovered in culture.

scholarly journals Management of Daylily Rust with Different Fungicides and Application Methods

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 921-926 ◽  
Author(s):  
W. B. Dong ◽  
S. N. Jeffers ◽  
J. W. Buck
Keyword(s):  
Active Ingredient ◽  
Field Experiments ◽  
Disease Incidence ◽  
Management Options ◽  
Lesion Development ◽  
Thiophanate Methyl ◽  
Foliar Sprays ◽  
Application Methods ◽  
Bare Root ◽  
Foliar Fungicide

The objectives of this study were to assess the efficacy of various fungicides applied as root dips, soil drenches, or foliar sprays to daylily plants grown in containers and planted in the field to manage rust caused by Puccinia hemerocallidis. Soil drenches and foliar sprays were evaluated in field experiments in Griffin, GA in 2010 and 2011. Dipping bare-root daylily plants for 5 min in azoxystrobin, tebuconazole, or thiophanate-methyl significantly reduced lesion development compared with nontreated control plants. Drenches with azoxystrobin, fluoxastrobin, or tebuconazole, each at three rates (0.06, 0.12, and 0.24 g of active ingredient [a.i.]/container), significantly reduced development of rust lesions on container-grown daylily plants for up to 9 weeks after treatment and 6 weeks after inoculation. One early-season drench of azoxystrobin at 0.12 g a.i‥/plant provided season-long reduction in disease incidence and disease progress that was comparable with foliar sprays with azoxystrobin or chlorothalonil applied at 14-day intervals. Dip or drench applications of fungicides would allow growers to diversify rust management options and could reduce the number of foliar fungicide applications.

Resistance of Eucalyptus Spp. To Invasion by Phytophthora cinnamomi

1985 ◽  
Vol 33 (4) ◽  
pp. 409 ◽  
Author(s):  
JT Tippett ◽  
TC Hill ◽  
BL Shearer
Keyword(s):  
Phytophthora Cinnamomi ◽  
Field Studies ◽  
Laboratory Method ◽  
Lesion Development ◽  
Eucalyptus Marginata ◽  
Mine Site ◽  
Inoculation Methods ◽  
Close Proximity ◽  
Moderately Resistant

The resistance of 21 Eucalyptus spp. to Phytophthora cinnamomi Rands was assessed using wound inoculation methods. Aggressive lesions were observed in Eucalyptus marginata Uarrah) only. Lesion development was initially compared in E. marginata and E. calophylla (moderately resistant). Further comparisons were made of lesions in roots and stems of E. marginata, E. calophylla, E. patens and E. Wandoo growing in close proximity, in forest south-east of Perth. E. wandoo was the most resistant; the fungus failed to establish. As stems proved convenient for inoculation, summer stem inoculation trials were made to rate the resistance of 21 Eucalyptus spp. grown on a rehabilitated mine site. Lesions formed in the species of the Monocalyptus and Corymbia subgeneric groups but did not develop in species of the subgenus Symphyomyrtus. An alternative laboratory method of rating susceptibility of roots to invasion was also tested. Excised roots of three eucalypts, Banksia grandis and Xanthorrhoea preissii were inoculated and incubated at 25°C. Length of the root invaded was recorded; results were not well correlated with those from field studies.

scholarly journals Efficacy of Soil and Foliar-applied Azadirachtin in Combination with and in Comparison to Soil-applied Imidacloprid and Foliar-applied Carbaryl Against Japanese Beetles on Roses

2007 ◽  
Vol 17 (3) ◽  
pp. 316-321 ◽  
Author(s):  
Justin M. Vitullo ◽  
Clifford S. Sadof
Keyword(s):  
Untreated Control ◽  
Field Trials ◽  
Popillia Japonica ◽  
Adult Beetle ◽  
Foliar Sprays ◽  
Soil Drench ◽  
Field Plots ◽  
Weekly Application

This study evaluated azadirachtin and imidacloprid for their ability to reduce injury by Japanese beetles [Popillia japonica (Coleoptera: Scarabaeidae)] on floribunda-type roses (Rosa sp. ‘Acadia Sunrise’), either applied to foliage or as a soil drench. Roses were arranged in field plots and exposed to resident adult beetle populations. Insecticides were evaluated in field and laboratory trials. Laboratory assays of leaves collected from plants 14 days after soil applications of azadirachtin were less preferred by adult beetles than those collected from untreated controls. Plants in field trials that received soil treatments of either imidacloprid or azadirachtin had defoliation levels that were <8% throughout the entire season, whereas untreated control plants were 20% defoliated. Addition of foliar sprays to soil applied insecticides provided no added protection to foliage. Rose blooms were more difficult to protect with both foliar and soil-applied insecticides. Bloom injury of untreated controls varied between 20% and 30%, while plants receiving soil applications of azadirachtin varied between 0.2% and 18%. Soil applications of imidacloprid provided somewhat better protection of blooms with injury ranging between 0.2% and 8%. Foliar applications of azadirachtin gave no added protection to blooms of plants treated with imidacloprid. Adding carbaryl foliar treatments every 2 weeks improved control to <2% injury, a level that was comparable to weekly application of carbaryl. The potential for using soil-applied azadirachtin to reduce the need for foliar applications of carbaryl in rose gardens is discussed.

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