A Review of the Association of Ants with Mealybug Wilt Disease of Pineapple

The literature concerning the association between ants and the mealybugs causing pineapple wilt disease is surveyed. A great deal of data on this subject has been published in the relatively obscure technical papers and reports of the defunct Pineapple Research Institute of Hawaii. This review article is an attempt to bring this information to a broader audience and examine it in the context of related research reported in mainstream publications to create a meaningful synthesis. Two species of mealybugs, Dysmicoccus brevipes (Cockerell) and D. neobrevipes Beardsley, are associated with wilt disease of pineapple under field conditions. A third species, Pseudococcus longispinus (Targioni-Tozzetti) induces wilt symptoms in laboratory experiments, but not under field conditions. The symptoms of wilt disease and the geographic distribution of the pineapple mealybug complex are described. The history of the discovery of the disease, the disease etiology, the association of mealybugs with wilt, and the mutualism between ants and mealybugs on pineapple are discussed in detail. At least 28 different species of ants tend mealybugs on pineapples. Pheidole and Solenopsis are the ant genera most commonly associated with pineapple mealybugs throughout the world. The ants and natural enemies associated with mealybugs on pineapple are reviewed as part of a discussion of the role of ants in promoting mealybug infestations. Finally, management techniques for wilt, including ant and mealybug control, are reviewed

Use of media and public-domain Internet sources for detection and assessment of plant health threats

Event-based biosurveillance is a recognized approach to early warning and situational awareness of emerging health threats. In this study, we build upon previous human and animal health work to develop a new approach to plant pest and pathogen surveillance. We show that monitoring public domain electronic media for indications and warning of epidemics and associated social disruption can provide information about the emergence and progression of plant pest infestation or disease outbreak. The approach is illustrated using a case study, which describes a plant pest and pathogen epidemic in China and Vietnam from February 2006 to December 2007, and the role of ducks in contributing to zoonotic virus spread in birds and humans. This approach could be used as a complementary method to traditional plant pest and pathogen surveillance to aid global and national plant protection officials and political leaders in early detection and timely response to significant biological threats to plant health, economic vitality, and social stability. This study documents the inter-relatedness of health in human, animal, and plant populations and emphasizes the importance of plant health surveillance

Airway Microbiota and Pathogen Abundance in Age-Stratified Cystic Fibrosis Patients

Bacterial communities in the airways of cystic fibrosis (CF) patients are, as in other ecological niches, influenced by autogenic and allogenic factors. However, our understanding of microbial colonization in younger versus older CF airways and the association with pulmonary function is rudimentary at best. Using a phylogenetic microarray, we examine the airway microbiota in age stratified CF patients ranging from neonates (9 months) to adults (72 years). From a cohort of clinically stable patients, we demonstrate that older CF patients who exhibit poorer pulmonary function possess more uneven, phylogenetically-clustered airway communities, compared to younger patients. Using longitudinal samples collected form a subset of these patients a pattern of initial bacterial community diversification was observed in younger patients compared with a progressive loss of diversity over time in older patients. We describe in detail the distinct bacterial community profiles associated with young and old CF patients with a particular focus on the differences between respective “early” and “late” colonizing organisms. Finally we assess the influence of Cystic Fibrosis Transmembrane Regulator (CFTR) mutation on bacterial abundance and identify genotype-specific communities involving members of the Pseudomonadaceae, Xanthomonadaceae, Moraxellaceae and Enterobacteriaceae amongst others. Data presented here provides insights into the CF airway microbiota, including initial diversification events in younger patients and establishment of specialized communities of pathogens associated with poor pulmonary function in older patient populations

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effect of Neem Oil, Monocrotophos, and Carbosulfan on Green Leafhoppers, Nephotettix virescens (Distant) (Homoptera: Cicadellidae) and Rice Yields in Thailand

Field trials were conducted in Thailand to determine the effect of Thai neem seed oil, monocrotophos (Azodrin), and carbosulfan (Posse) on rice yields (Oryza sativa L., variety RD7). Neem-treated plots did not yield significantly more rice than control plots. Plots treated with monocrotophos or carbosulfan had significantly higher yields than control plots or neem-treated plots. The rice yields were correlated with the levels of three insect species: Nephotettix virescens (Distant) (Homoptera: Cicadellidae), Nilaparvata lugens (Stal) (Homoptera: Delphacidae), and Chilo sp. (Lepidoptera: Pyralidae). Only N. virescens exceeded its economic threshold. More than 95% of the variation in yield data could be explained by the N. virescens levels 36 days after transplanting, N. virescens populations were reduced by applications of monocrotophos and carbosulfan. N. virescens was not effectively controlled by neem seed oil. N. virescens control with monocrotophos or carbosulfan at economic threshold appears to significantly increase rice yields

Effect of Eucalyptus dives Extracts on Pheidole megacephala (Fabricius) (Hymenoptera: Formicidae)

Eucalyptus dives extracts repelled starved Pheidole megacephala (Fabricius) from sucrose solutions in choice tests

Interactions of Ants (Hymenoptera: Formicidae) and Mealybugs (Homoptera: Pseudococcidae) on Pineapple

Ant and mealybug interactions were studied in a pineapple field near Honolua on the island of Maui, Hawaii. Big-headed ants (Pheidole megacephala (F.)) were found to have a positive association with gray pineapple mealybugs (Dysmicoccus neobrevipes Beardsley) but no association with pink pineapple mealybugs (D. brevipes (Cockerell)). Sticky trap collections revealed that D. neobrevipes and D. brevipes are dispersed by the wind. Field experiments indicated that both species of mealybugs could establish on pineapple plants, even in the absence of ants. The positive association between P. megacephala and D. neobrevipes was not due to ants transporting mealybugs, but could have resulted from ants deterring natural enemies or removing honeydew

The ecological significance of the big-headed ant in mealybug wilt disease of pineapple

Thesis (Ph. D.)--University of Hawaii at Manoa, 1992.Includes bibliographical references.Microfiche.xiii, 116 leaves, bound ill. 29 cmWhen ants are managed in pineapple fields, the mealybug population rapidly declines. Why ants are so vital to mealybug survival in pineapple is the subject of this dissertation. Historically, three explanations were given for the importance of ants to mealybugs in pineapple. One hypothesis was that ants protect mealybugs from natural enemies. Another hypothesis was that ants perform an essential task for the mealybugs by consuming the mealybug honeydew, suggesting that mealybugs would drown in their own waste material were it not for the sanitation activities of the ants. According to another hypothesis ants are the primary or sole means of mealybug dispersal in pineapple. In other words, the ants actually bring the mealybugs into the field and distribute them from one pineapple plant to another. These explanations are frequently presented in the literature as facts, not hypotheses; although little supporting evidence has been published on the topic. Through a series of field and laboratory experiments I have provided evidence that: 1. Big-headed ants (BHA), Pheidole megacephala (F.), are essential for the survival of gray pineapple mealybugs (GPM), Dysmicoccus neobrevipes Beardsley, in pineapple fields. 2. BRA suppress predator populations. 3. BRA do not aid GPM through sanitation. 4. GPM are not dispersed by BRA. 5. First instar GPM are dispersed by the wind. In short, the data presented in this dissertation do not support the dispersal or sanitation hypothesis, but do support the hypothesis that BRA protect GPM from natural enemies. Thus, when ants are eradicated from a pineapple field, the resulting increase in predation (and possibly parasitization) of mealybugs brings wilt disease under control. The pineapple industry has unintentionally been relying on biological control for wilt management. Once the most efficient species of natural enemies are identified it should be possible to artificially augment their populations and reduce the need for insecticides. The discovery that GPM are dispersed by the wind will be useful for monitoring populations with sticky traps. Wind barriers and traps may be also be used to prevent, or decrease the severity of GPM infestations

Effectiveness of brown planthopper predators: Population suppression by two species of spider, Pardosa pseudoannulata (Araneae, Lycosidae) and Araneus inustus (Araneae, Araneidae)

The most abundant natural enemies found in Cambodian rice field are spiders, mostly Araneus inustus and Pardosa pseudoannulata. These two hunting and wolf spider, respectively, are believed to actively contribute to brown planthopper (BPH) population control. However, how much each species attacks prey in Cambodian field condition is unknown. We conducted field experiments in Cambodia during the wet season at two locations, a famner's fields at Takeo and at CARDI, using both field cages and natural conditions. Cages were sprayed with insecticide to remove all pre-existing insects in the cages and then washed after 10 days to reduce insecticide residue. Results confirmed BPH inside the cage were killed by the insecticide. A known BPH population was reared inside the cages starting with 3 pairs of adults. Temporary cages were removed after counting second instar BPH and permanent cages were left in place. Spiders were released into the cages for 15 days. In permanent cages either two individual A. inustus or P. pseudoannulata were allowed to feed on BPH prey. Both spider species have the same killing ability in dense prey populations, but predation is higher for Pardosa at low prey density. In uncaged field environments (where more than just BPH prey are available) with a spider/BPH ratio 1:3 to 1:11 BPH mortality was 78–91%. Within 15 days in permanent cages spiders caused 100% BPH mortality at an average predator/prey ratio of 1:5 to 1:14. At a ratio of 1:18 or higher there was some BPH survival in cages