In Vitro Sensitivity to Timorex Gold of Five Different Fungi Under Two Different Methods

In vitro sensitivity of Didymella bryoniae, Fusarium oxysporum, Trichoderma spp, Sclerotium rolfsii and Thielaviopsis basicola

to the botanical fungicide Timorex Gold (Melaleuca alternifolia) under the “Paper disk diffusion” and the “Poisoning agar” testing methods.

1

M. Barbier 1

University of Florida-IFAS, Plant Medicine Program, Gainesville, FL, 32611

BACKGROUND

PRODUCT

Timorex Gold is a botanical fungicide which contains tea tree oil (TTO) as active ingredient. TTO is an

essential oil steam distilled from the Australian plant Melaleuca alternifolia. TTO contains over 100

components, mostly monoterpenes, sesquiterpenes and their alcohols. TTO as a natural essential oil is

known as an effective antiseptic, fungicide and bactericide, and has many safe and effective uses in the

health and cosmetics industry. Its use against plant pathogens has very few investigations, mainly done

by Biomor Israel Ltd., which did developed an organic product labeled as Timorex Gold, this product

contains 23.8% of TTO, and has been reported to be effective against broad spectrum plant diseases in

various crops with no phytotoxicity to plant. In vitro tests done by Biomor showed that Timorex Gold at

100 – 1,000 ppm inhibited spore germination of powdery mildew fungus. Timorex Gold has been

evaluated in greenhouse, and open field studies at foliar spray rates of 5,000 – 10,000 ppm inhibited

late blight disease caused by Phytophthora infestans and controlled powdery mildews in various crops

such as tomato, cucumber and pepper plants. It was as good as or better than standard treatments. (1)

PATHOGENS

Didymella bryoniae is the causal organism of Gummy stem blight (GSB) in many cucurbits, including

watermelon, cantaloupe, cucumber, pumpkin, squash, muskmelon, and other melons. Infection on

watermelon and cantaloupe is commonly seen in Florida, and the disease can cause significant

production losses when conditions are ideal for the spread of this fungal pathogen. The disease is also

known as black rot due to its characteristic appearance on infected fruits. (2)

Fusarium oxysporum f. sp. lycopersici (Sacc.) W.C. Snyder and H.N. Hans, a soilborne plant pathogen in

the class Hyphomycetes, causes Fusarium wilt specifically in tomato. This disease was first described by

G.E. Massee in England in 1895. It is of worldwide importance where at least 32 countries had reported

the disease, which is particularly severe in countries with warm climate. At one time, the disease nearly

destroyed tomato production in parts of Florida and the southeastern states of United States. However,

the development and use of resistant cultivars have nearly eliminated the concern over this disease.

Three physiological races of this pathogen have been reported. Race 1 is the most widely distributed

and has been reported from most geographical areas. Although, race 2 was first reported in Ohio in

1940, it did not become widespread or of economic concern until its discovery in Florida in 1961. Since

then, it was rapidly reported in several of the states and in several other countries, including Australia,

Brazil, Great Britain, Israel, Mexico, Morocco, the Netherlands, and Iraq. Race 3 was reported in 1966 in

Brazil. Thereafter, it has been found in Australia and in Florida and California. (3)

Trichoderma spp are important biological control agents used in plant disease management. They are

imperfect fungi, with their teleomorph perfect stage belonging to Hypocreales of Ascomycetes. They are

capable of secreting hydrolytic enzymes and cause mycoparasitism on fungal pathogens of plants. Besides,

they produce antibiotics and toxins that inhibit the fungal plant pathogens. (3)

Sclerotium rolfsii an omnivorous, soilborne fungal pathogen, causes disease on a wide range of

agricultural and horticultural crops. Although no worldwide compilation of host genera has been

published, over 270 host genera have been reported in the United States alone. Susceptible agricultural

hosts include sweet potato (Ipomea batatas), pumpkin (Cucurbita pepo L.), corn (Zea mays), wheat

(Triticum vulgare) and peanut (Arachis hypogea). (3)

Thielaviopsis basicola (Berk. & Br.) Ferraris is a soil inhabitant that attacks more than 100 plant species

in thirty three families. Members of the Fabaceae, Solanaceae, and Cucurbitaceae families are

especially affected by this fungus. Thielaviopsis basicola can be found in all regions of the world,

especially in regions with cool climates. Causes a disease which is known as 'black root rot' and this

name is based on darkly pigmented chlamydospores that form in the root cells of hosts and giving a

'blackened' appearance to the root tip. The black root rot fungus is a member of the Hyphomycetes,

order Moniliales, family Dematicaceae. General symptoms are root rot and branch dieback. Black root

rot can affect a wide range of woody and herbaceous plants including tobacco, holly, begonia, geranium,

poinsettia, and pansy. (3)

MATERIALS AND METHODS

METHODS

Paper disk diffusion method

The paper disk diffusion test is also known as the Kirby-Bauer disk-diffusion method, is a means of measuring the effect of an antimicrobial agent against fungi grown in culture. A filter-paper disks, is soak into the compound to be evaluated for 15 minutes, and later the disk is take it out by letting it dry for an hour. Then, the disk is placed on the surface of the agar. Subsequently, a piece of 5 mm of growing fungi is placed over the paper. The compound diffuses from the filter paper into the agar. If the compound is effective against the fungi at a certain concentration, no growth or reduction on the

growth will be observed. The inhibition of the growth is known as inhibition zone. The diameter of the growth zone of the fungi is measured in millimeters during six days each 24 hours. Thus, the size of the zone of the fungi growth is a measure of the compound's effectiveness: the smaller the area around the filter disk, the more effective the compound.

Poison agar method

Potato dextrose agar (PDA) is prepared and mixed with the concentrations of the compound to be

evaluated (in percentage or parts per million - ppm) and placed to autoclave. Then, the compounds are

allowed to warm to 50ºC. The Poisoning Agar (PA) containing the different concentrations of the

evaluating compound are poured into 90 mm Petri dishes to allowed cooling. Afterwards, the cultures

of the fungi to be evaluated are cut into 5 mm x 5 mm squares. Each square is placed in the centre of a

paper disk which is placed over the surface of the PA. Each treatment is at least replicated three times

inside the disk. Subsequently, the plates have to be placed into an incubator at 22-24°C for six days.

Diameter growth is measured around each block and results are recorded in a daily basis.

MATERIALS

One isolate of each evaluating fungi were tested. These isolates were sub-cultured from cultures stored at the Clinical Trials Program laboratory.

The concentrations of Timorex Gold evaluated were prepared by dissolving in water. The final fungicide concentrations were adjusted to achieve 2,500; 5,000; 10,000 and 20,000 ppm. These concentrations were based on the recommended rates of Timorex Gold label for use in different crops in Central America due to the product is in the registration process in the United States.

For the disk diffusion method, cellulose discs were placed for 15 minutes in four clean petri dishes containing each the test solution that was previously prepared. Later, the discs were placed in the interior side of the petri dishes lid for sixty minutes to evaporate free moisture from the disc surface. After the one hour dry time the moist discs were placed onto the potato dextrose agar so that each plate (three per isolate per concentration) contained two treated discs and one untreated check disc.

For the poisoning agar method, potato dextrose agar (PDA) was prepared using the same solutions that were previously used for the disk diffusion. After taking the PA containing the different concentrations of the evaluating compound from the autoclave, the bottles allowed to warm to 50ºC. They were poured into 90 mm Petri dishes and allowed to solidify before placing three untreated disks per petri dish. Two disks of each concentration were prepared in order to have a total of six repetitions.

Inoculation

The cultures of the fungi to be evaluated were cut into 5 mm x 5 mm squares. Each square was placed in the centre of each paper disks that were placed over the surface of the Disk diffusion and the Poisoning Agar petri dishes.

The inoculated plates were incubated for 144 hours at 25°C with 12 hours of light. The radial growth of the test fungi were measured and recorded.

For the Disk diffusion the experiment was conducted three times, because efficacy levels of Timorex Gold over the tested fungi did differ illogically between concentrations. The second time, a modification in the solvent and drying time steps in the methodology was performed to check if the solvent and/or the drying times were the reason of the differences between the treatments. No differences were found in the solvent and drying time steps in the methodology.

RESULTS

Statistics

For the diffusion disk method for each treatment – fungi tested three petri dish were prepared

containing each petri dish two treated discs (DD) and one untreated check disk (DD-CTL), giving a total of

6 repetitions for treatments and 3 repetitions for the check controls. For the poisoning agar method for

each treatment – fungi tested two petri dish were prepared containing each petri dish three untreated

discs that were place over the treated agar for the treatments and over the untreated agar for the

absolute control, giving a total of 6 repetitions for the treatments and the control. A total of thirteen

treatments were analyzed as indicated below:

Treatment

Petri dishes

Disks inside petri

dishes

Total disks taken as a repetition

Absolute control – PDA 2 3 6 Disk diffusion 2,500 ppm TG 3 2 6 Disk diffusion 2,500 ppm control 3 1 3 Poison Agar 2,500 ppm TG 2 3 6 Disk diffusion 5,000 ppm TG 3 2 6 Disk diffusion 5,000 ppm control 3 1 3 Poison Agar 5,000 ppm TG 2 3 6 Disk diffusion 10,000 ppm TG 3 2 6 Disk diffusion 10,000 ppm control 3 1 3 Poison Agar 10,000 ppm TG 2 3 6 Disk diffusion 20,000 ppm TG 3 2 6 Disk diffusion 20,000 ppm control 3 1 3 Poison Agar 20,000 ppm TG 2 3 6

Statistical analyses were performed using SAS 9.2. Fisher’s Least Significant Difference (LSD) test was

used at a confidence level of 95%, therefore, p values <0.05 were considered significant.

Didymella bryoniae

The evaluation of the disk diffusion (DD) method showed that the four concentrations of Timorex Gold

have limited or no inhibition of the radial growth of the isolate tested when compared with each

individual control inside the same petri dish (bottom disk of each picture), after 144 hours of fungi were

placed in petri dishes the inhibition was negative and growth stimulation was as follows: 2,500 = 0%;

5,000 ppm = 1%; 10,000 ppm = 4%; and 20,000 ppm = 1%.

DD - 2,500 ppm DD - 5,000 ppm DD - 10,000 ppm DD - 20,000 ppm

On the other hand, when the four concentration of Timorex Gold where compared with the absolute

control with no product inside the petri dish, a limited inhibition of the radial growth of the isolate was

observed. After 144 hours of fungi were placed in petri dishes, inhibition was as follows: 20,000 ppm

rate = 18%; 10,000 ppm = 17%; 5,000 ppm = 22%; and 2,500 = 20%.

Absolute control

The evaluation of the poison agar (PA) method showed that the four concentrations of Timorex Gold

inhibit the radial growth of the isolate tested when compared with absolute control. After 144 hours of

fungi were placed in petri dishes, Didymella bryoniae inhibition was as follows: 20,000 ppm = 93%;

10,000 ppm = 59%; 5,000 ppm = 50%; and 2,500 = 35%;

PA - 2,500 ppm PA - 5,000 ppm PA - 10,000 ppm PA - 20,000 ppm

Means of radial fungi growth

Treatment 24 h 48 h 72 h 96 h 120 h 144 h Absolute control – PDA 6.2 CDE 25.7 A 39.2 A 45.0 A 51.3 A 70.0 A Disk diffusion 2,500 ppm TG 6.3 BCDE 17.0 D 32.0 DE 36.2 E 43.8 I 56.0 BCD Disk diffusion 2,500 ppm control 7.0 ABC 17.7 CD 33.7 BC 38.0 D 45.7 G 56.0 BCD Poison Agar 2,500 ppm TG 5.3 EF 17.7 CD 23.7 F 31.0 F 36.3 J 45.8 E Disk diffusion 5,000 ppm TG 6.7 ABCD 18.8 BC 34.2 B 39.2 BCD 47.7 C 54.3 CD Disk diffusion 5,000 ppm control 6.0 CDEF 18.7 BC 33.0 BC 40.0 BC 48.3 B 54.0 D Poison Agar 5,000 ppm TG 5.3 EF 11.5 E 21.3 G 25.0 G 27.8 K 35.3 F Disk diffusion 10,000 ppm TG 6.8 ABC 17.8 BCD 32.8 CD 38.5 D 46.3 F 58.0 B Disk diffusion 10,000 ppm control 7.7 A 19.3 B 33.0 C 39.7 BC 47.3 D 56.0 BCD Poison Agar 10,000 ppm TG 5.7 DEF 7.0 F 13.0 H 16.7 H 20.5 L 28.8 G Disk diffusion 20,000 ppm TG 6.3 BCDE 17.5 CD 31.5 E 38.0 D 44.0 H 57.3 B Disk diffusion 20,000 ppm control 7.3 AB 19.0 BC 33.0 C 40.7 B 47.0 E 56.7 BC Poison Agar 20,000 ppm TG 5.0 F 5.0 G 5.0 G 5.0 I 5.0 M 5.0 H Different letters indicate that the means are significantly different.

Fusarium oxysporum



individual control inside the same petri dish (bottom disk of each picture). After 144 hours of fungi were

placed in petri dishes, the inhibition was negative and growth stimulation was as follows: 2,500 = 8%;

5,000 ppm = -1%; 10,000 ppm = 8%; and 20,000 ppm = 6%.




observed. After 144 hours of fungi were placed in petri dishes, inhibition was as follows: 20,000 ppm

rate = 4%; 10,000 ppm = -2%; 5,000 ppm = 18%; and 2,500 = 17%.

Absolute control



fungi were placed in petri dishes, Fusarium oxysporum inhibition was as follows: 20,000 ppm = 78%;

10,000 ppm = 47%; 5,000 ppm = 29%; and 2,500 = 21%;



Treatment 24 h 48 h 72 h 96 h 120 h 144 h Absolute control – PDA 6.3 BCD 21.0 A 33.8 A 41.3 A 45.5 A 48.3 A Disk diffusion 2,500 ppm TG 6.8 BC 17.3 BCD 28.7 BC 33.5 CDE 36.5 CDE 40.3 CD Disk diffusion 2,500 ppm control 8.3 A 20.3 A 27.7 CD 30.0 FG 35.0 DEF 37.3 DE Poison Agar 2,500 ppm TG 5.5 DE 17.2 CD 26.7 D 29.7 FG 32.5 FG 38.2 DE Disk diffusion 5,000 ppm TG 5.8 CDE 15.7 DE 27.7 CD 31.8 DEF 34.5 EF 39.7 D Disk diffusion 5,000 ppm control 7.0 B 16.7 CD 26.7 D 31.3 EF 34.7 DEF 40.3 CD Poison Agar 5,000 ppm TG 5.5 DE 13.7 E 22.0 E 26.8 G 30.2 G 34.2 E Disk diffusion 10,000 ppm TG 7.2 B 18.0 BC 30.2 B 37.5 B 41.0 B 49.2 A Disk diffusion 10,000 ppm control 7.0 B 19.3 AB 30.0 B 36.7 BC 39.3 BC 45.7 AB Poison Agar 10,000 ppm TG 5.8 CDE 9.7 F 12.3 F 17.0 H 20.5 H 25.7 F Disk diffusion 20,000 ppm TG 5.7 DE 17.0 CD 29.7 B 35.8 BC 37.8 BCD 46.5 AB Disk diffusion 20,000 ppm control 6.3 BCD 17.0 CD 29.0 BC 35.0 BCD 36.0 DE 44.0 BC Poison Agar 20,000 ppm TG 5.0 E 5.8 G 7.5 G 9.5 I 10.2 I 10.8 G Different letters indicate that the means are significantly different.

Trichoderma spp




placed in petri dishes the inhibition was as follows: 20,000 ppm = 2%; 10,000 ppm = 5%; 5,000 ppm =

15%; and 2,500 = 3%.




observed. After 144 hours of fungi were placed in petri dishes, inhibition was as follows: 20,000 ppm =

14%; 10,000 ppm = 17%; 5,000 ppm = 17%; and 2,500 = 20%.

Different letters indicate that the means are significantly different.

Absolute control



fungi were placed in petri dishes, Trichoderma spp inhibition was as follows: 20,000 ppm = 87%; 10,000

ppm = 65%; 5,000 ppm = 35%; and 2,500 = 0%.



Treatment 24 h 48 h 72 h 96 h 120 h 144 h Absolute control - PDA 5.3 A 8.3 A 14.2 A 31.0 A 40.8 AB 56.5 AB Disk diffusion 2,500 ppm TG 5.0 A 6.2 BCDE 9.8 BC 24.3 B 34.3 B 45.3 D Disk diffusion 2,500 ppm control 5.0 A 6.7 BCDE 11.7 AB 25.7 AB 37.0 AB 46.7 D Poison Agar 2,500 ppm TG 6.0 A 7.5 AB 10.3 B 25.0 B 35.2 AB 58.3 A Disk diffusion 5,000 ppm TG 5.0 A 6.0 CDE 10.3 B 25.5 B 35.0 AB 46.8 D Disk diffusion 5,000 ppm control 5.0 A 6.3 BCDE 11.0 B 24.0 B 37.0 AB 55.0 ABC Poison Agar 5,000 ppm TG 5.0 A 5.5 DE 9.2 BC 14.7 C 22.0 C 37.0 E Disk diffusion 10,000 ppm TG 5.0 A 6.8 BCD 9.7 BC 26.5 AB 36.0 AB 46.7 D Disk diffusion 10,000 ppm control 5.0 A 7.3 ABC 10.0 BC 27.3 AB 39.3 AB 49.0 BCD Poison Agar 10,000 ppm TG 5.2 A 5.3 E 7.5 CD 9.8 CD 13.5 D 19.7 F Disk diffusion 20,000 ppm TG 5.0 A 7.2 ABC 11.3 B 27.2 AB 41.5 A 48.8 CD Disk diffusion 20,000 ppm control 5.2 A 7.3 ABC 10.7 B 26.3 AB 39.3 AB 50.0 BCD Poison Agar 20,000 ppm TG 5.0 A 5.3 E 6.2 D 6.5 D 7.3 D 7.3 G

72 h

ou

rs

48

ho

urs

Sclerotium rolfsii




placed in petri dishes the inhibition was as follows: 2,500 ppm = 12%; 5,000 ppm = 14%; 10,000 ppm =

9%; and 20,000 ppm = 8%. After 72 hours the growth of all treatment reached the borders of the petri

dish and no differences were recorded when compared with the control.


When the four concentration of Timorex Gold where compared with the absolute control with no

product inside the petri dish, a similar limited inhibition of the radial growth of the isolate was observed.

After 48 hours of fungi were placed in petri dishes, inhibition was as follows: 20,000 ppm = 6%; 10,000

ppm = 5%; 5,000 ppm = 10%; and 2,500 = 19%. After 72 hours the growth of all treatment reached the

borders of the petri dish and no differences were recorded when compared with the control.

Absolute control 48 h Absolute control 72 h Absolute control 96 h Absolute control 144 h



fungi were placed in petri dishes, Sclerotium rolfsii inhibition was as follows: 20,000 ppm = 86%; 10,000

ppm = 38%; 5,000 ppm = 10%; and 2,500 = 2%. After 96 hours the growth of treatments 2,500 ppm and

144

ho

urs

9

6 h

ou

rs

5,000 ppm reached the borders of the petri dish and no differences were recorded when compared with

the control. Treatments 10,000 ppm and 20,000 ppm showed that these concentrations of Timorex

Gold inhibited the radial growth of the isolate tested when compared with absolute control until 144

hours after fungi were placed in petri dishes. Sclerotium rolfsii inhibition was as follows: 20,000 ppm =

74% and 10,000 ppm = 6%.



Treatment 24 h 48 h 72 h 96 h 120 h 144 h Absolute control - PDA 9.8 A 47.8 C 70.0 A 70.0 A 70.0 A 70.0 A Disk diffusion 2,500 ppm TG 6.8 CD 38.7 H 70.0 A 70.0 A 70.0 A 70.0 A Disk diffusion 2,500 ppm control 7.3 BCD 44.0 F 70.0 A 70.0 A 70.0 A 70.0 A Poison Agar 2,500 ppm TG 9.3 AB 29.8 I 51.3 B 68.5 B 70.0 A 70.0 A Disk diffusion 5,000 ppm TG 7.7 ABCD 43.1 G 70.0 A 70.0 A 70.0 A 70.0 A Disk diffusion 5,000 ppm control 9.0 ABC 50.0 A 70.0 A 70.0 A 70.0 A 70.0 A Poison Agar 5,000 ppm TG 6.3 D 23.5 J 42.3 C 63.3 C 70.0 A 70.0 A Disk diffusion 10,000 ppm TG 7.8 ABCD 45.5 D 70.0 A 70.0 A 70.0 A 70.0 A Disk diffusion 10,000 ppm control 8.7 ABCD 50.0 A 70.0 A 70.0 A 70.0 A 70.0 A Poison Agar 10,000 ppm TG 6.8 CD 13.0 K 27.7 D 43.2 D 50.2 B 65.5 B Disk diffusion 20,000 ppm TG 7.3 BCD 44.7 E 70.0 A 70.0 A 70.0 A 70.0 A Disk diffusion 20,000 ppm control 8.3 ABCD 48.7 B 70.0 A 70.0 A 70.0 A 70.0 A Poison Agar 20,000 ppm TG 6.8 CD 7.0 L 7.8 E 10.0 E 12.3 C 18.2 C

Thielaviopsis basicola




placed in petri dishes was growth inhibition for the 2,500 = 14% and 20,000 ppm = 4%, being negative

and growth stimulation was observed for the 5,000 ppm = 23% and 10,000 ppm = 3%.


Same behavior was observed when the four concentration of Timorex Gold where compared with the

absolute control with no product inside the petri dish. After 144 hours of fungi were placed in petri

dishes was growth inhibition for the 2,500 = 5% and no growth for 20,000 ppm = 0%, being negative and

growth stimulation was observed for the 5,000 ppm = 20% and 10,000 ppm = 7%.

Absolute control



fungi were placed in petri dishes, Thielaviopsis basicola inhibition was as follows: 20,000 ppm = 83%;

10,000 ppm = 78%; 5,000 ppm = 50%; and 2,500 = 38%.



Treatment 24 h 48 h 72 h 96 h 120 h 144 h Absolute control - PDA 5.0 B 6.3 ABC 11.2 CD 17.0 C 22.3 B 28.8 B Disk diffusion 2,500 ppm TG 5.0 B 7.7 AB 13.0 BC 20.5 AB 24.0 AB 27.3 B Disk diffusion 2,500 ppm control 5.0 B 7.3 AB 17.0 A 23.0 A 25.3 AB 31.7 AB Poison Agar 2,500 ppm TG 5.0 B 5.2 C 7.3 E 9.0 D 12.5 C 18.0 C Disk diffusion 5,000 ppm TG 5.0 B 8.2 A 12.7 BC 20.0 B 26.0 A 34.7 A Disk diffusion 5,000 ppm control 5.0 B 7.3 AB 14.0 B 21.3 AB 23.7 AB 28.3 B Poison Agar 5,000 ppm TG 5.0 B 6.0 BC 7.2 EF 7.5 DE 9.7 C 14.3 C Disk diffusion 10,000 ppm TG 5.0 B 6.7 ABC 10.2 D 22.0 AB 24.7 AB 30.7 AB Disk diffusion 10,000 ppm control 5.0 B 5.3 C 12.3 BCD 22.0 AB 25.0 AB 29.7 AB Poison Agar 10,000 ppm TG 5.0 B 5.0 C 5.0 F 5.5 E 6.0 D 6.3 D Disk diffusion 20,000 ppm TG 5.2 A 7.7 AB 13.3 BC 20.2 AB 23.7 AB 28.8 B Disk diffusion 20,000 ppm control 5.0 B 6.7 ABC 12.3 BCD 21.7 AB 24.0 AB 30.0 AB Poison Agar 20,000 ppm TG 5.0 B 5.0 C 5.0 F 5.0 E 5.0 D 5.0 D Different letters indicate that the means are significantly different.

OBSERVATIONS, CONCLUSIONS AND RECOMMENDATIONS

Observations

The major components of tea tree oil (active ingredient of Timorex Gold) are monoterpenes which area

characterized by a very high vapor pressure ranging from 5.7 Pa (α – Terpineol) to 544 Pa (α – pinene).

In the disk diffusion method, the growths measurements of the evaluated fungi were very similar

between the treated disks with Timorex Gold and the check disks (no impregnated) in all evaluated

treatments. When compared the check disks with the absolute control of each treatment there were

statistically significant differences between all inside check disks and the absolute control. In Fusarium

oxysporum also some depigmentation were observed for the 10,000 and 20,000 ppm treatments.

In the poison agar method, significant differences were observed between all treatments; the absolute

control and the treatments with the disk diffusion method. These significant differences were observed

in the four evaluated rated in the five evaluated fungi.

Conclusions

Our research indicates that In Vitro evaluations of Timorex Gold under the disk diffusion method gives

inconsistent data regarding the efficacy of the product. Under the poison agar method, all rates showed

some efficacy, but just the 10,000 and 20,000 ppm rates showed effective inhibition of the five fungi

isolations after the 144 hours evaluation period.

Recommendations

The efficacy of Timorex Gold should be evaluated in greenhouse and then in open field. There is a fact

that the high vapor pressure of the product components must be taken into account to avoid

inadequate use of dilution volume and spraying pressure.

For further information contact Marcel Barbier to any of the following contact information:

e-mails: [email protected] or [email protected]

Phone: + 1 (800) 576-5134 or Fax: + 1 (800) 803-2790

Acknowledgements

The authors would like to thank Zena Armella for assisting in the photographical activities of this study.

References

1. Timorex Gold – Central America label. Biomor Israel Ltd. 2008

2. Management of Gummy Stem Bliht (Black Rot) on Cucurbits in Florida. Mathews L. Paret,

Nicholas S. Dufault, and Stephen M. Olson. Plant Pathology Department, Florida Cooperative

Extension Service, IFAS, University of Florida. 2011.

3. Soilborne Plant Pathogens. North Carolina State University. NCSU Department of Plant

Pathology, 2518 Gardner Hall, Raleigh, NC 27695-7616.

mailto:[email protected]

mailto:[email protected]

Documents

In Vitro Sensitivity to Timorex Gold of Five Different Fungi Under Two Different Methods