The frequency of the blackspot disease caused by digenetic trematodes in fish was tested as an indicator of the quality of water in the watershed of Lake Guaíba. Samples were standardised and quarterly made using a seine net at eleven sites in the basin. A total of 53,408 individuals of 66 specimens pertaining to 22 families and 8 orders were collected and analysed. The highest frequency of the disease was found in Astyanax fasciatus. The simple Chi-Squared test applied to the species showed statistically significant frequency of occurrence for three sampled sites. Two of these sites showed the highest frequencies for two consecutive sampling periods of one year and the best levels of water quality. Results of this study suggest that the association between high frequency of infestation by a parasite that causes the blackspot disease in fish, and environments with less degradation in water quality, recorded from physical, chemicals and microbiological variables, could be used as an indicator of water quality in these environments.
varieties ‘Hamlin’ (early), ‘Pera’ (mid-season), and ‘Valência’ (late) to citrus blackspot was assessed in a commercial grove, under conditions of natural infection. Disease severity and disease incidence were assessed in 100 fruits of 100 plants of each variety, every 15 days, from the first appearance of symptoms in the field until harvest. The monomolecular model was fitted to the data of the disease progress curves for the three varieties. The rate parameter (r) of the disease progress curve was not different for the three varieties. Varieties ‘Hamlin’, ‘Pera’ and ‘Valência’ present the same degree of susceptibility to the MPC.
Citrus blackspot (CBS) caused by Guignardia citricarpa is one of the most serious Brazilian citrus diseases. This study aims to assess the interference of three application volumes in spray deposition citrus fruit, as well as fruit growth and rainfall effects on spray deposit reduction during the CBS control period. The experiment was carried out in a commercial citrus orchard, with sixteen-year-old trees of the Valencia variety, in Mogi Guaçu, São Paulo State, Brazil. The spray volumes were: 3.5 (1333L ha -1 ), 4.5 (1714L ha -1 ) and
An alternative strategy that may be adopted is the biological control. This type of control is considered a promising method to reduce the pesticide use and protect crops, thus adding value to the product going to the market, as it is based on procedures that reduce the pathogen population in a sustainable way and may be part of an integrated system for disease control. For papaya, the biological control is still little studied, with some reports on biocontrol agents such as bacteria and yeasts against several post-harvest fungi (Bautista- Bañosa et al. 2013, Lima et al. 2014). However, in the literature, there is no research on the blackspot disease of papaya biocontrol. Thus, this is a pioneering study of great importance for the selection of isolates with mycoparasitic potential against A. caricae.
In the current study, various treatments were used in the acceleration of decomposition in Sicilian lemon leaves as an auxiliary measure to control citrus blackspot. The treatments tested were: 1) urea (12.5 g/L); 2) calcium nitrate (12.5 g/L); 3) dolomitic limestone (2 t/ha); 4) Embiotic® (commercial composting accelerator - 1% of the activated product); 5) Soil-Set® + Compostaid® (0.75 mL/L + 0.75 g/L; and 6) control. Treatments 1, 2, 4, and 5 were applied in solution under the plant’s crowns (800 L/ha), while dolomitic limestone was applied to only one side of the plant using a drop spreader. The most efficient treatment in reducing leaf weight was with urea, calcium nitrate and Soil-Set® + Compostaid®. In relation to cellulose, Embiotic® and Soil-Set® + Compostaid® reduced the same content showing a high efficiency in the decomposition rate of the lemon leaves. As for the dehydrogenase activity, there was an increase in the first and second evaluations, followed by a reduction in the second and third observations, amounting to 9.90% for dolomitic limestone, and 72.41% for the control. The results showed the viability of accelerating decomposition of citrus leaves fallen on the soil as a supplementary control measure for Guignardia citricarpa.
Ondračková et al. (2004) observed that the standard length and body weight of more heavily infected, parasitised fish were significantly higher than in unparasitised fish. Some studies have indicated that blackspot agents can result in reduced survival, growth and health of fish in natural systems (Quist et al., 2007). Harrison and Hadley (1982) pointed out that several authors have investigated the effects of the trematodes metacercariae in the health of fish hosts, however there were no consistent results. Bush et al. (2001) suggested that blackspot disease is known to reduce energy reserves in infected fish, which is likely to negatively affect the immune system, and thus, facilitate secondary infections by other parasites and diseases. Lane and Morris (2000) and Herman (1990) emphasised that the stress caused by parasites lowers the tolerance of fish to environmental stressors. Paradis and Chapleau (1994) suggested that blackspot disease did not influence the biology of the fish genus Phoxinus, since the condition index and the gonadosomatic index in females are not affected by the level of infection.
ABSTRACT - Genetic resistance represents a sustainable alternative to disease control in papaya crop. The purpose of this study was to evaluate the use of testers to estimate combining ability and select hybrids resistant to blackspot, phoma spot and chocolate spot. The experiment was conducted in a randomized block design with two replications and 20 plants per plot. The severity of phoma spot and blackspot on leaves and the lesion area of blackspot and chocolate spot on fruits were evaluated in two seasons. The combining ability of the following crosses is negative for all traits: tester ‘JS 12’ with ‘Sunrise Solo’ and ‘Kaphoro Solo PV’; tester ‘Americano’ with ‘Caliman M5’, ‘Sunrise Solo’, ’Baixinho de Santa Amália’ and ‘Waimanalo’; and tester ‘Maradol’ with ‘Caliman G’, ‘Caliman AM’ and ‘Sunrise Solo PT’. These results may be useful in breeding for disease resistance by hybridization.
With the exception of sour orange (Citrus aurantium L.) and its hybrids and Tahiti limes [C. latifolia (Yu. Tanaka) Tanaka], almost all Citrus spp., especially late maturing cultivars, are susceptible to this disease (Kotze, 1964, 2000). Several different types of blackspot symptoms including hard spot, virulent spot, and false melanose occur on affected fruit and reduce its value for the fresh market (Kotze, 2000). Premature fruit drop due to blackspot causes significant yield loss in Brazil, and probably in other citrus regions of the world.
The blackspot symptoms were characterized by elliptical to circular spots with a whitish center and a dark- brown to black border, 2-3 cm and rarely more than 5 cm in diameter. Sporulation is not observed in such lesions. The leaf blotch symptoms are characterized by straw- colored, elliptical lesions of varying sizes without any definite margin, and sometimes appearing as long stripes with abundant sporulation of conidia resembling D. avenae (Mehta, 1998a, 1999). Mehta (1998) reported that the conidia produced by the blackspot isolates were slightly shorter than those produced by leaf blotch isolates, and that some of the leaf blotch isolates produced pycnidia on artificial media, whereas none of the blackspot isolates produced any pycnidia (Mehta, 1999b). Although some morphological differences between the isolates causing two different symptoms were observed, the genetic relationship between them was not clear, and therefore work regarding breeding for resistance against these diseases was hampered.
Citrus blackspot (CBS), caused by Guignardia citricarpa (=Phyllosticta citricarpa), is one of the main fungal diseases in citriculture. All varieties of sweet orange (Citrus sinensis) and species such as C. limon, C. paradisi, C. reticulata and C. deliciosa are susceptible to the pathogen (HU et al., 2014). It was first reported in Australia in 1895 (SUTTON and WATERSTON, 1966) and has since spread to other citrus growing regions, such as southern and central Africa, South America and Asia, becoming a major
The progress rates of anthracnose and blackspot were higher when crop residues were present (p ≤ 0.05), which suggests that both pathogens can survive in these residues that perpetuate within-field inoculum in the ab- sence of flowers or fruit. The mucilage around the conid- ia of Colletotrichum sp. allows for pathogen survival for long periods in plant debris. In addition, Colletotrichum spp. is known to survive in several species of wild and cultivated plants (Silva and Michereff, 2013). The high disease incidence at the beginning of the season is prob- ably related to the high survival capacity of this patho- gen. Moreover, as a perennial crop, guava trees remain in the field for many years enabling a continued increase in the incidence of pathogens that survive in crop resi- dues. Therefore, crop residues may be sources of local inocula besides other planting areas. Further studies are recommended, preferably with evaluations performed over a longer period. According to Piccinin et al. (2005), among the measures to control postharvest diseases of guava, especially quiescent diseases, pruning diseased branches, cleaning the orchard and immediately burn- ing all crop residues are of paramount importance to re- duce the amount of inocula in the field.
6a (3b). Antennomeres I-II black; male connexival spines reaching middle of genital segment I (Fig. 7); female connexival spines long and curved, reaching apex of genital segments ............................................................ C. palmaris 6b. Antennomeres I-II brown; male connexival spines not reaching middle of genital segment I (Fig. 11); female connexival spines short, not reaching apex of genital segments ............................................................... C. regulus 7a (2b). Pronotum dark brown to black, with a pair of elongated light maculae centrally; middle tarsi with claws; connexival spines present .............................................. [Limnogonus] 8 7b. Pronotum dark brown to black, with an oval central light macula; middle tarsi without claws; connexival spines absent ............................................................... [Neogerris] 9 8a (7a). Male genital segment I with a single spine-like projection (Fig. 24) ............... Limnogonus aduncus aduncus 8b. Male genital segment I with a rounded gibbosity in front of the posterior spine-like projection .................... L. recurvus 9a (7b). Pronotum of apterous forms wider than long, exposing most of mesonotum (Fig. 12); male genital segment II with a tuft of setae on each side (Fig. 13) ...... Neogerris visendus 9b. Pronotum of apterous forms longer than wide, reaching at least the middle of mesonotum (Fig. 14); male genital segment II without tuft of setae ..................................... 10 10a (9b). Eyes short and globose (Fig. 15); pronotum of apterous forms usually reaching only the middle of mesonotum (Fig. 14), rarely longer; fore femur with an ovate blackspot on distal third of outer surface; posterior margin of male genital segment I with a distinct central notch ................. N. lotus 10b. Eyes longer, not globose, pronotum of apterous forms always covering most of mesonotum, almost reaching metanotum (Fig. 16); fore femur with a brown
Color in alcohol. Ground color dark yellow in dorsal region of body and head, gradually lighter on sides. Dark brown longitudinal lines usually forming a zigzag pattern between longitudinal rows of scales, except immediately above anal-fin base; more conspicuous along the longitudinal axis of the body, more visible in specimens larger than 50.0 mm SL (Fig. 1). Small black chromatophores scattered over rays of all fins. Adipose fin without distinctive marks, except for the anterodorsal border smoothly light gray pigmented. Small blackspot vertically expanded at base of median caudal-fin rays (Figs. 1-2). Specimens measuring 42.0-50.0 mm SL with one or two faint and vertically elongate humeral spots. Color pattern of specimens smaller than 41.0 mm SL similar to that of large specimens, but always with two black vertically elongate humeral spots; anterior diffuse, located over first to fourth perforated lateral-line scales and sometimes extending over horizontal series of scales just above lateral line. Second humeral spot darker, located over seventh to eighth perforated lateral-line scales and sometimes extending over horizontal series of scales just above lateral line. Specimens larger than 60.0 mm SL without humeral spots (Figs. 1-2). Specimens up to 45 mm SL with chevron-shaped striae posteriorly diverging from longitudinal line, following miosepta. The remaining fins with dispersed dark Anal-fin rays iii-v,27-30 (iii,28*; rarely 26, mode = 29,
ABSTRACT – The ability of isolates of Bacillus subtilis and Trichoderma spp. to control citrus blackspot (CBS) was investigated in ´Natal´ sweet orange orchards. The first experiment was conducted during the 2001/2002 season and four isolates of B. subtilis (ACB-AP3, ACB-69, ACB-72 and ACB-77), applied every 28 days, alone or in combination were tested and compared with fungicide treatments. Two other experiments were carried out during the 2002/2003 season, where the same isolates of Bacillus and two isolates of Trichoderma (ACB-14 and ACB-40) were tested being applied every 28 days in the second experiment, and every 15 days in the third experiment. In the first experiment, the treatment with ACB-69 differed statistically from the control, but did not differ from other biological control agents or mixture of Bacillus isolates. In the second experiment, the treatments with ACB-69 and ACB-AP3 resulted in smaller disease index compared with the control treatment. However, this result was not repeated in the third experiment, where the isolates were applied every 15 days. Disease severity was high in both evaluated seasons and the fungicide treatment was the most effective for disease control.
Blackspot, caused by Guignardia citricarpa, is one of the main diseases affecting citrus fruits. UV-C irradiation is known to have potential to be used as an alternative method to supplement or replace the use of fungicides, especially because it promotes resistance against pathogens. The aim of this work was to evaluate the in vitro effects of UV-C irradiation on G. citricarpa development and on the control of blackspot in postharvest orange. Additionally, changes in skin color of the fruit as a result of UV-C treatment were evaluated. Mycelial growth, conidial germination and appressoria formation were evaluated in vitro after fungal exposure to different irradiation doses. Also, ‘Valência’ oranges naturally infected were submitted to different irradiation doses to check the possibility of in vivo control. Fruit were stored at 25ºC/80% RH and evaluated 3, 7, 10 and 14 days after treatment and area under the disease progress curve was calculated. UV-C irradiation affected conidial germination of G. citricarpa and apressorium formation. UV-C irradiation was not able to control citrus blackspot on fruit at a satisfactory level; however, incidence of quiescent blackspot lesions was lower on postharvest ‘Valência’ orange treated with 7.28 and 15.66 kJ m -2 . Low UV-C doses did not affect the visual aspect of fruit. Thus, UV-C irradiation can contribute for the
FIGURE 1 - Incidence (%) of the major postharvest diseases (● - anthracnose; ■ - blackspot; ▲ - Fusicoccum rot) in ‘Kumagai’ (A and B) and ‘Pedro Sato’ (C and D) guavas, collected every fifteen days from November to April of 2009/10 and 2010 /11 at CEASA (Campinas, SP) (A and C) and CEAGESP (São Paulo, SP) (B and D), and kept during 10 days at 25°C. Average data from surveys conducted in 2009/10 and 2010/11. Vertical lines represent the standard error.
including dorsocentral seta and ending on medial margin of sublateral posterior blackspot, in some specimens additional pair of lateral vittae present, from transverse suture to lateral margin of sublateral black spots; setulae fine, yellow to pale brown, evenly distributed except on black spots and posterior margin. Scutellum entirely yellow, subshining, with microtrichia less dense than on scutum. Subscutellum entirely microtrichose, entirely black or often with medial orange spot. Mediotergite entirely black, broadly microtrichose dorsolaterally, with broad triangular to semicircular shiny ventromedial area. Katepisternum with usually wedge-shaped blackspot anteroventral to katepisternal seta. Meron with large blackspot dorsal to hind coxa. Anatergite and katatergite with large posteroventral blackspot, usually reaching mediotergite. Anepisternum with second seta up to 1/2 as long as largest (dorsalmost) seta. LEGS: Male fore femur with numerous long thin setae anteriorly and ventrally, normal anterodorsal and ventral rows of setae poorly or not differentiated. WING (Fig. 1J): Pattern with 4-5 distinct bands. Apical band complete, only partially separated from subapical band by marginal hyaline spot in cell r 1 midway between apices of R 1 and R 2+3 that extends at most 1/2 of distance to R 2+3 ; otherwise confluent with costa. Subapical band constricted or narrowly interrupted along vein M, if interrupted, basal part extended to vein M and distal part (moderate sized, brown, ovoid, apical spot) separated from it by hyaline area smaller
Integument orange-reddish. Vertex finely punctuate. Upper ocular lobes with six rows of ommatidia. Apex of antennomere VII reaching apices of elytra in males. Scape gradually thickened toward apex, shallowly punctuated. Hairs on inner side of antennomere III short and more concentrated on apical half. Sides of prothorax with lateral, central, concolo- rous, short spine, and short blackspot near anterior margin; lateroanterior tubercle discrete. Pronotum with two black an- terior tubercles; behind them two black, elongate spots not reaching basal edge; entire pronotal surface with irregular wrinkles, including tubercles. Mesosternum without tubercle. Each elytron with three ivory spots: first one basal, as broad as distance between spot and scutellum, and followed by small black mark; second and third ones median elliptical, not con- tiguous but very close to each other, surrounded with black; outer spot beginning at middle of inner spot. Black triangular spot anterior to black spines. Epipleura with teeth near base of elytron, yellowish on anterior 2/3. Punctuation more concen- trated at anterior half, without rough punctures. Profemora entirely orange. Meso- and metafemora orange with apices and inner spines black. Tibiae and tarsi orange.
origin of lymphoid cells in the penaeid prawn Penaeus monodon. Dis. Aquat. Org. 40: 85-92. Bell, T.A. and Lightner, D.V. 1988. A Handbook of Normal Penaeid Shrimp Histology. World Aquaculture Soceity, Baton Rouge, USA. 114 p. Boonyaratpalin, S., Boonyaratpalin, M., Supamattaya, K. and Toride, Y. 1995. Effects of peptidoglycan (PG) on growth, survival, immune response and tolerance to stress in black tiger shrimp, Penaeus monodon. In: Disease in Asian Aquaculture II. (eds. Shariff, M., Arthur, J.R. and Subasinghe, R.P.) pp. 469-477. Fish Health Section, Asain Fisheries Society, Manila, Phillippins.