Os danos causados no desenvolvimento vegetativo e na produção de frutos da gravioleira pelo vírus da mancha-amarela da gravioleira (Soursop yellow blotch virus, SYBV), foram estudados durante os anos de 2000 a 2004 em um experimento com dois tratamentos: plantas sadias e plantas doentes, dispostos em blocos ao acaso, com oito repetições e quatro plantas por parcela. Foram avaliados, anualmente, a altura da planta, diâmetro do caule, número e peso de frutos, sendo que a produção foi monitorada a partir do segundo ano de plantio. As médias relativas à altura de planta, diâmetro do caule, número e peso de frutos das parcelas foram computadas, analisadas estatisticamente e comparadas pelo teste F. As plantas de ambos tratamentos foram originadas de mudas enxertadas, sendo as plantas doentes obtidas por meio de enxertias com propágulos de plantas infectadas com o SYBV. A doença reduziu em 65,11% e 46,72% a altura e o diâmetro do caule, respectivamente, e em 94,7 % e 99,2 % o número e o peso de frutos em relação às plantas sadias.

Growth and yield losses on soursop plants due the Soursop yellow blotch virus (SYBV) disease were studied during the years 2000 to 2004 in an experiment with two treatments: healthy and SYBV diseased plants. The experiment was disposed in a completely randomized block design with 8 replications with 4 plants per plot. Plant height, trunk diameter, number and weight of fruits were evaluated annually. Data, as plot means, was computed, statistically analyzed and compared by F test. Plants of both treatments were obtained by grafting with buds from healthy and SYBV infected plants. The disease caused percent reductions of 65.11, 46.72, 94.7 and 99.2 in plant height, trunk diameter, in fruit number and fruit weight, respectively.

Resultados preliminares de um experimento, em execução desde setembro de 2000 no Campo Experimental de Pacajus, CE, para avaliar um sistema de policultivo com fruteiras, são relacionados e discutidos neste trabalho. Dez espécies foram plantadas em uma área de 1,2 ha, em covas alternadas e divergentes em relação às linhas laterais, sendo que cada planta de uma espécie foi circundada por plantas de outras espécies. Após 15 meses, as espécies bananeira, mamoeiro e goiabeira foram substituídas por cupuaçuzeiro, pupunheira e abacateiro, respectivamente. A não adaptação da bananeira pode ter como causa os efeitos danosos dos ventos e maior irradiação solar, devido ao maior espaçamento utilizado no sistema em relação ao cultivo comercial. A mangueira, o sapotizeiro, o cajueiro, a aceroleira e a gravioleira estão com bom desenvolvimento. E, com exceção da mangueira e do sapotizeiro, todas já estão em frutificação. Nos 34 meses de avaliação, verificou-se que a recomposição natural da flora entre as fileiras foi prejudicada pela carência de nutrientes químicos e matéria orgânica do solo, o que pode ter favorecido, também, o ataque de pragas e doenças.

Preliminary results of an experiment carried out in the Experimental Field of Pacajus, CE, Brazil, established in September 2000, to evaluate intercropping systems of tropical fruit trees are discussed. Ten species were planted in 1.2 ha, in a way that each row had two species in alternate and divergent position in relation to the lateral lines, so that each plant of one species was surrounded by plants of different species. After 15 months banana, papaya, and guava species were replaced by cupuacu, peach palm, and avocado, respectively. Banana was bad adapted to the system and this could be caused by the harmful effects of wind and higher irradiation due large plant spacing utilized in relation to the commercial plantation. Mango, sapodilla, cashew tree, acerola, and soursop tree adapted well to the system. During the 34 month-period of evaluation the regrowth of the natural flora between rows has been impaired by the low soil fertility and organic matter which may also have favored pests and diseases attack.

Deltamethrin-impregnated PVC dog collars were tested to assess if they were effective in protecting dogs from sand fly bites of Lutzomyia longipalpis and Lu. migonei. A protective effect against Old World species Phlebotomus perniciosus was demonstrated before. Four dogs wearing deltamethrin collars and three dogs wearing untreated collars (not impregnated with deltamethrin) were kept in separate kennels for over eight months in a village on the outskirts of Fortaleza in Ceará, Brazil. Periodically, a dog from each group was sedated, placed in a net cage for 2 h in which 150 female sand flies had been released 10-15 min before. Lu. longipalpis were used 4, 8, 12, 16, 22, 27, and 35 weeks after the attachment of the collars. Lu. migonei were used 3, 7, 11, 15, 22, 26, and 36 weeks after attachment. During 35 weeks, only 4.1% (81 of 2,022) Lu. longipalpis recovered from the nets with the deltamethrin collared dogs were engorged, an anti-feeding effect of 96%. Mortality initially was over 90% and at 35 weeks was 35% with half of the sand flies dying in the first 2 h. In contrast, 83% of the 2,094 Lu. longipalpis recovered from the nets containing the untreated collared dogs were engorged and the mortality ranged from zero to 18.8% on one occasion with 1.1% dying in the first 2 h. Similar findings were found with Lu. migonei: of 2,034 sand flies recovered over this period, only 70 were engorged, an anti-feeding effect of 96.5%, and mortality ranged from 91% initially to 46% at 36 weeks. In contrast, engorgement of controls ranged from 91 to71% and a mortality ranged from 3.5 to 29.8%. These studies show that deltamethrin impregnated collars can protect dogs against Brazilian sand flies for up to eight months. Thus, they should be useful in a program to control human and canine visceral leishmaniasis.