www.iaard.net International Association of Advances in Research and Development International Journal of Advanced Agricultural Research International Journal of Advanced Agricultural Research, 2015, 1(1),16-22 Effectiveness of fungicides to control garlic rust ( puccinia allii (rudolphi.)) at haramaya, eastern Ethiopia Worku Mengesha 1* Mashilla Djene 2, Azene Tesfaye 3 1Department of Plant Sciences, Aksum University, Shire Campus P.O. Box 314, Shire,Ethiopia, 2Shool of Plant Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia 3 Biodiversity research Center, Arba Minch University, Ethiopia *Corresponding author e-mail: [email protected] , ……………………………………………………………………………………………………………… Abstract: Garlic rust is caused by an air-borne obligate pathogen called Puccinia allii (Rudolphi) and seriously reduces the productivity of Alliaceae, especially garlic (Allium sativum) and onion (Allium cepa) crops. A field experiment was carried out at Haramaya University experimental field in 2012/13 cropping season to compare the efficacies of some fungicides against garlic rust using a local garlic cultivar (Chiro). The experiment was laid out in a randomized complete block design in three replications. Four levels of fungicides (bayleton, mancozeb, propiconazole, ridomil) and control. The four fungicides sprayed varied significantly in disease incidence, disease severity, area under disease progress curve (AUDPC), yield and yield components. Propiconazole was found to be the most effective chemical of all the tested fungicides and showed disease severity of 3.72% only at 128 days after planting (DAP). Keywords: Allium sativum , disease incidence, disease severity, fungicides, Puccinia allii …………………………………………………………………………………………………………………………….. 1. Introduction home consumption and as a source of income to Garlic ( Allium sativum L.) an important many peasant farmers in many parts of the country. spice crop belongs to the family Alliaceae and is the In Ethiopia, the total area under garlic production second most widely used Allium next to onion [1]. It in 2013/2014 reached 16,411.19 ha and the is originated on the northwestern side of the Tien- production was estimated to be over 159,093.575 Shan Mountains of Kirgizia in the arid and semi arid tons; CSA, 2014. areas of central Asia [2] . Garlic plant, the green tops Garlic rust is readily identified by as well as the bulbs are principally used as spice for experienced person under field conditions. Early flavoring and seasoning vegetable and meat dishes, symptoms consisted of small (< 2 mm diameter), it gives the food a delightful fragrance. It usually circular to elongate, white flecks that occurred on dehydrated for industrial and home use. Its folk both sides of the infected leaves. As disease medicinal use includes treatment of whooping progressed, these small spots expand into oblong cough, lung diseases, stomach complaints (as lesions. The leaf tissue covering the lesions rupture healing of ulcer of the intestines) and disorders due to fungal structures that develop internally, and resulting from child birth and as a specific for colds, masses of the characteristic orange uredospores sore eyes and ear-ache. become visible in pustules [5] . The unique flavor and health-promoting Severely infected leaves can be almost functions of garlic attributed to its rich content of entirely covered with pustules, resulting in complete sulfur-containing compounds, i.e., alliin, g- yellowing, wilting, and drying of the foliage. As the glutamylcysteine, and their derivatives (Chia-Wen disease progresses, a second, darker spore type (the Tsai et al., 2012). Garli c yields allicin, a powerful so-called teliospores in the fruiting bodies known as antibiotic and antifungal compound (phytoncide). It telia) may also occur on the same leaves, resulting also contains alliin, ajoene, enzymes, vitamin B, in black pustules (fruiting bodies called telia). minerals, and flavonoids. The composition of the Severe rust on garlic and other Alliums can cause bulbs is approximately 84.09% water, 13.38% organic extensive loss of foliage and form concentric groups matter, and 1.53% inorganic matter, while the leaves on the spot periphery [7] . are 87.14% water, 11.27% organic matter, and 1.59% Despite its importance and increased [3] inorganic matter . production in many parts of the world, garlic In Ethiopia, the Alliums group (garlic, onion productivity is relatively low due to genetic and and shallot) are important bulb crops produced by several environmental factors (both biotic and small and commercial growers for both local use abiotic factors) that affect its yield and yield related [4] and export markets . These crops are produced for traits. Numerous and prominent production Worku Mengesha et al., Page No. 16 International Journal of Advanced Agricultural Research, 2015, 1(1),16-22 problems accounted for the low yield of garlic in intervals with the rate of 0.5 kg ha -1 with 100 L of Ethiopia include lack of proper planting material, water. inappropriate agronomic practices, absence of Mancozeb (Manzate ): It is a broad spectrum proper pest and disease management practices and fungicide. Applied in 7-day intervals with the rate marketing facilities [4] . of 3.5 kg ha -1. Even though fungicides are able to control Ridomil Gold EC/Copper (mefenoxam plus the disease, they are different in effectiveness. copper): Broad spectrum fungicide containing Hence, this research experiment was initiated with 4.8% metalaxyl and 60% copper hydroxide the objective: to evaluate the efficacies of some effective against both lower and true fungi. Applied selected fungicides against garlic rust. in 7-day intervals with the rate of 3.5 kg ha -1. 2. Materials and methods Propiconazole (Tilt): A protective fungicide for The study was conducted at Haramaya beets, carrots, celery, onions, and corn. Applied University Research Station (Raaree), Ethiopia, with the rate of 1000 ml ha -1 in 10-day intervals. under rainfed conditions during the year 2012/13 Garlic rust was assessed by scoring disease main cropping season. Haramaya Agricultural incidence and disease severity as well as area Research Station is located in eastern Ethiopia about under disease progress curve (AUDPC). 520 km away from Addis Ababa. The site is Disease incidence percentage (plants showing specifically located at latitude of 9 o26’N, longitude symptoms divided by total observation) was of 42 o30’E and an altitude of 1980 m.a.s.l. The rainy assessed from 10 randomly selected plants on the season of the area is bimodal type with an average onset of the first symptom appearance and the annual rainfall of 780 mm. The short rainy period assessment was carried out on weekly basis. (Belg ) extends from March to May and the long Disease severity was also recorded and estimated in rainy season ( kiremt) extends from June to percentage of the leaf surface covered with lesions. September or early October. The mean annual It was assessed from all leaves of a plant and the minimum and maximum temperatures are 8.3 and average was recorded for the respective plant. 23.4 oC, respectively [8] . The soil is generally alluvial Average severity of the 10 plants per plot was used type (heavy clay). for statistical analysis. A uniform sized local garlic (chiro) variety The area under disease progress curve (AUDPC) and four fungicides (bayleton, mancozeb, ridomil was calculated for each treatment from the and propiconazole) and a control. There were a total assessment of disease severity using: of 5 treatments replicated three times. Each plot n-1 consists of five rows of 2 m length with a distance AUDPC = Σ 0.5[(x i + 1 + x i)(t i + 1 - ti)] ------ (Shaner of 0.30 m between rows. The treatments were and Finney, 1977) [9] arranged in a randomized complete block design i=1 (RCBD). The gangway between plots and Where, x = is disease severity at i th observation, n = replications was 1 and 1.5 m wide, respectively. The is the total number of days disease assessed and t = plots were fertilized with diammonium phosphate is the time at the i th observation (in days numbered (DAP) and urea at the rate of 200 (92 kg P 2O5 + 36 sequentially beginning with the initial assessment). kg N) and 150 (69 kg N) kilograms per hectare, Data of yield and yield components and other respectively, i.e. a total of 105 kg N ha -1. The urea agronomic parameters were collected as follows. was applied in split, half at the time of planting and 1. Days to maturity: This refers to the number of the remaining half three weeks after planting and days taken from emergence to 75% leaf fall. DAP fertilizer was applied once at the time of 2. Plant height (cm): It refers to the average height planting. Planting was done on 25 July 2012. of 10 plants of each plot measured from ground Fungicide application was started at the level to the tip of the pseudo-stem at maturity. onset or appearance of rust on the foliage. During 3. Total yield (t/ha): Total yield was recorded from application of each of the fungicides a plastic sheet the middle three rows of each plot after curing and was used to prevent drift problems. The four converted to tons per hectare. fungicides were applied in the following manner per 4. Bulb weight (g): The average weight of 10 bulbs factory recommendation. taken from each plot after curing. Triadimefon 125 EC (Baylton): Bayleton 125 5. Bulb diameter (mm): The average diameter of EC Fungicide is a systemic fungicide with 10 randomly sampled bulbs from each plot was protective and curative action. Applied in 10-day measured by using digital caliper after curing. Worku Mengesha et al., Page No. 17 International Journal of Advanced Agricultural Research, 2015, 1(1),16-22 6. Number of cloves per bulb: This refers to the 3.Results and discussion average number of cloves of 10 bulbs taken from Garlic rust onset and intensity each plot.