Fernando Carneiro de Albuquerque

Three new pathogens infecting antilles cherry in the State of Pará

Em plantios uniformes, a aceroleira (Malpighia glabra) tem sido afetada por doencas que causam manchas e malformacao nos frutos, tornando estes improprios para consumo in natura. A partir de 1999, tres novas doencas caracterizadas pelo aparecimento de manchas foliares e queda da folhagem vem sendo observadas em plantacoes localizadas nos municipios de Santa Izabel do Para e Igarape Acu. Apos isolamento, exame das estruturas morfologicas e testes de patogenicidade em mudas de acerola, os isolados foram identificados como Calonectria ilicicola (anamorfo: Cylindrocladium parasiticum) que causa manchas foliares relativamente grandes atingindo ate 7 cm de comprimento, de coloracao marrom-escura que coalescem atingindo grande extensao da area foliar e causando a queda de ate 50% das folhas; Corynespora cassiicola que provoca manchas necroticas de formato irregular, com bordas marrom-escuras e centro branco, circundadas por um halo amarelo nitido; Myrothecium roridum que causa manchas concentricas de coloracao cinza. O fungo C. cassiicola tem sido relatado causando doencas em varios hospedeiros na regiao amazonica, enquanto C. ilicicola infeta outros hospedeiros, nos Estados do Maranhao e Para.

Resistência de piperáceas nativas da Amazônia á infecção causada por Nectria haematococca f. sp. piperis

The resistance of Piper aduncum, P. arboreum, P. carniconnectivum, P. colubrinum, P. hispidinervium, P. hispidum, P. hostmannianum, P. nigrum, P. tuberculatum and Piper sp. to the infection caused by two Nectria haematococca f. sp. piperis isolates was detected under laboratory and shade house conditions. Due to their high susceptibility, black pepper (Piper nigrum) plants were used as control. When grown in soil infested with the isolate from P. aduncum (Adu), no root rot symptoms were observed on the majority of Piper spp., except on Piper sp. and black pepper. However, in soil infested with the isolate from P. nigrum (Nig) root rot was noticed on black pepper, although not on the other Piper spp. Significant differences (p<0.01) were observed when stems of Piper spp. plants were inoculated with Adu and Nig isolates. On P. nigrum stems typical lesions were followed by yellowish, stem blight and death of plants were observed, while on Piper spp. canker-like tissues around stem lesions were detected, evidencing the high resistance of these related species. These results showed that the isolate from P. aduncum has no ability to colonise Piper spp. root tissues and that at least seven related species are highly resistant to N. haematococca f. sp. piperis. This suggests that these species may be used either as rootstocks or for somatic hybridisation and protoplast fusion in amelioration studies aiming to control Fusarium diseases on black pepper.

White-thread blight: five new hosts in the state of pará, brasil

Since the first description of Pellicularia koleroga Cooke, at present classified as Ceratobasidium stevensii (Burt) Venkat. (sin: Corticium koleroga (Cooke) v. Hohn., Koleroga noxia Donk, Botryobasidium koleroga Cooke) by Deslandes (Bol. Fitossanitario 1:197, 1944), more than 40 important agricultural and forestry species were reported to be damaged by the white-thread blight, making evident the importance of that pathogen to the Amazon region (Albuquerque, Seminario Tecnico, EMBRAPA-IPEAN, 1973; Silva et al., Fitopatol. bras., 8:601, 1983; Lourd & Alves, Fitopatol. bras., 12:88, 1987; Furtado, Manual de Fitopatol., 1997; Benchimol & Muller, Embrapa-CPATU, Comunicado Tecnico 99, 1999; Gasparotto & Silva, Fitopatol. bras., 24:469, 1999). C. stevensii penetrates the plant by natural chaps or twig axils, showing up as whitish mycelial cords (rhizomorphs) that develop upon the host twigs and leaves, causing them to dry. The dead leaves remain hanged on the twigs by the pathogen mycelium as a characteristic sign of the white-thread blight (Figure 1). Morphological and physiological characteristics of the pathogen and disease control were described by Roger, L. (Phytopathologie des Pays Chauds, Lechevalier, 1949). Surveys on Bragantina region plantings, State of Para, Brazil, detected damages caused by C. stevensii on Neem (Azadirachta indica A. Juss.), African mahogany (Khaya ivorensis A. Chev.), coconut (Cocos nucifera L.), banana (Musa L. cv. yangambi) and ornamental Ixora (Ixora coccinea L.). Reproduction of white-thread blight symptoms under greenhouse conditions was obtained about one week after mycelial PDA plug inoculation on the abaxial face of the young leaves of these hosts left in a dew chamber for 48 h. FIG. 1 Signs of Ceratobasidium stevensii (arrows) on (a) K. ivorensis; (b) A. indica; (c) I. coccinea; (d) C. nucifera; (e) Musa sp.

Mancha areolada causada por Thanatephorus cucumeris em mogno africano

African mahogany (Khaya ivorensis) introduced in Brazil in recent years has been preferred to reforest devastated areas to replace Brazilian mahogany (Swietenia macrophylla) due to its high-quality timber and its high resistance to Hypsiphyla grandella, the major pest of Brazilian mahogany. Since 1999 a high incidence of target leaf spot caused by Thanatephorus cucumeris has been observed in nursery and in field, in the States of Amazonas and Para (Brazil), causing numerous zonate lesions on mature leaves and 100% leaf fall in seedlings. Young leaves of diseased plants initially show little brown spots surrounded by a purple margin, while in mature plants the lesions are light brown exhibiting concentric rings resembling a target.

Incidence of Fusarium solani in cassava in the State of Pará, Brazil

This paper describes for the first time the occurrence of Fusarium solani infecting cassava (Manihot esculenta) in the State of Para.

Rot of corn caused by Rhizoctonia zeae in the state of Pará, Brazil

The occurrence of corn rot caused by Rhizoctonia zeae is reported for the first time in the State of Para, Brazil.

Coconut stalk rot caused by Cylindrocladium floridanum in the State of Pará, Brazil.

Center of Embrapa, Belem, PA. The fungus was inoculated in healthy fruits causing the same field symptoms and reisolated, fulfilling koch postulates. This is the first report of this pathogen on coconut in the State of Para, Brazil.

Pyricularia grisea causing leaf spots in banana produced by micropropagation

Pyricularia grisea causing leaf spots in banana produced by micropropagation Banana (Musa sp.) seedlings produced by micropropagation in the aclimatation stage have been infected by Pyricularia grisea causing necrotic leaf spot limiting the growth of the explants.

Detection of Phamerochaete salmonicolor in African mahogany in the State of Pará, Brazil

Detection of Phamerochaete salmonicolor in African mahogany in the State of Para, Brazil Two-year-old plants of African mahogany (Khaya ivorensis) growing at Embrapa Experimental Station in Belem and in the municipalities of Igarape-Acu and Santa Barbara have been infected by Phamerochaete salmonicolor, which causes pink disease. Pink disease is recorded for the first time in African Mahogany in the State of Para, Brazil. O mogno africano (Khaya ivorensis A. Chev.) tem sido uma das especies preferidas pelos reflorestadores no estado do Para. E uma arvore de grande importância para a regiao amazonica, devido ao seu alto valor economico e crescimento relativamente rapido, promovendo a recuperacao de areas alteradas (Falesi & Baena. Embrapa Amazonia Oriental,