Surrounding Vegetation, Climatic Elements, and Predators Affect the Spatial Dynamics of Bemisia tabaci (Hemiptera: Aleyrodidae) in Commercial Melon Fields

2019 ◽  
Vol 112 (6) ◽  
pp. 2774-2781 ◽  
Author(s):  
Thiago Nunes Pinto Felicio ◽  
Thiago Leandro Costa ◽  
Renato Almeida Sarmento ◽  
Rodrigo Soares Ramos ◽  
Poliana Silvestre Pereira ◽  
...  

Abstract Studying the spatial dynamics of pests allows the determination of abiotic and biotic factors affecting time and locations of pest attack to the crops. Such abiotic and biotic factors mainly include 1) climatic elements, 2) natural enemies, 3) phenological stage of plants, and 4) surrounding vegetation. Melon (Cucumis melo L. [Cucurbitales: Cucurbitaceae]) is among the most consumed fruit in the world, and the whitefly Bemisia tabaci (Gennadius) is among the main pests of this crop. This work aimed to determine the effects of surrounding vegetation, natural enemies, climatic elements, and stages of plants on the spatial dynamics of B. tabaci in commercial melon fields. Adult whitefly densities were monitored on four melon fields in a tropical climate region. Sampling location in crops was georeferenced. Experimental data were submitted to geostatistical analysis. The highest densities of B. tabaci occurred during hot periods experiencing lower rainfall, and when the surrounding area presented crops hosting B. tabaci, especially other melon farms. The density ratio of the predators (i.e., spiders and Geocoris sp.) were dependent on pest density. The pattern of field colonization by B. tabaci varies according to its density. Therefore, the surrounding vegetation, air temperature, and predators influence the spatial distribution of B. tabaci in melon fields. These results provide important information to melon farmers, assisting them to improve the management of B. tabaci in the field.

2018 ◽  
Vol 432 (1-2) ◽  
pp. 1-28 ◽  
Author(s):  
Jay Ram Lamichhane ◽  
Philippe Debaeke ◽  
Christian Steinberg ◽  
Ming Pei You ◽  
Martin J. Barbetti ◽  
...  

2018 ◽  
Vol 77 (3) ◽  
pp. 607-615 ◽  
Author(s):  
Ya-Fan Chan ◽  
Kuo-Ping Chiang ◽  
Yun Ku ◽  
Gwo-Ching Gong

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Vanessa da Silveira Duarte ◽  
Karin Westrum ◽  
Ana Elizabete Lopes Ribeiro ◽  
Manoel Guedes Corrêa Gondim Junior ◽  
Ingeborg Klingen ◽  
...  

Neozygites floridanais an obligate mite pathogenic fungus in the Entomophthoromycota. It has been suggested that resting spores of this fungus are produced as a strategy to survive adverse conditions. In the present study, possible mechanisms involved in the regulation of resting spore formation were investigated in the hostsTetranychus urticaeandTetranychus evansi. Abiotic and biotic factors mimicking conditions that we, based on earlier field studies, thought might induce resting spores in temperate and tropical regions were tested with isolates from Norway and Brazil. A total of 42 combinations of conditions were tested, but only one induced the formation of a high number of resting spores in only one isolate. The Brazilian isolate ESALQ1420 produced a large number of resting spores (51.5%) inT. urticaeat a temperature of 11°C, photoperiod of 10L:14D, and light intensity of 42–46 (μmol m−2 s−1) on nonsenescent plants (nondiapausing females). Resting spores of the BrazilianN. floridanaisolate ESALQ1421 were found at very low levels (up to 1.0%). Small percentages ofT. urticaewith resting spores (0–5.0%) were found for the Norwegian isolate NCRI271/04 under the conditions tested. The percentages of resting spores found for the Norwegian isolate in our laboratory studies are similar to the prevalence reported in earlier field studies.


Buletin Palma ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Novalisa T.E Lumentut ◽  
Sri Karindah ◽  
Meldy L.A Hosang

<p>The abundance of Brontispa longissima and its natural enemies on coconut palms have been explored in North Minahasa,South Minahasa and Southeast Minahasa Districts in February 2012 - January 2013. The aims of the research were to study the abundance of B. longissima an natural enemies in the field. The research was conducted on unproduced coconut palm and productive coconut palm. Sampling is done randomly plated or Stratified random sampling using quadrant system. The results showed that the abundance of B. longissima fluctuated, the highest abundance occurred in August and September 2012 in unproductive palms. In productive palms, the highest abundance of B. longissima at the altitude of 300-600 m above sea level occurred in August 2012, which was 70.3 individuals / young leaves, then at altitude &gt; 600 m above sea level occurred in September 2012, ie 64 individuals / young leaves, and at an altitude of &lt;300 m above sea level occurred in June 2012, which is 62 individuals / young leaves. Brontispa longissima natural enemies found at altitudes &lt;300 m above sea level, 300-600 m above sea level, and&gt; 600 m above sea level in unproduced coconut palms are parasitoid Tetrastichus brontispae, Chelisoches morio predator, and entomopathogen Metarhizium anisopliae var. anisopliae. The natural enemies found in productive coconut palm at three different altitudes are Tetrastichus brontispae parasitoids, and Chelisoches morio predators. Entomopatogen M. aanisopliae var. anisopliae is not found on the productivecoconut palms at all three altitudes. The abundance of natural enemies and percentage of parasitism in the three different altitudes both in unproductive coconut palm and productive coconut palm was low is between 0.33-14.47%. This is due to the influence of abiotic and biotic factors on the abundance of B. longissima.</p><p><strong><br /></strong></p><p><strong>ABSTRAK </strong></p><p>Kelimpahan Brontispa longissima dan musuh alaminya pada tanaman kelapa telah dieksplorasi di Kabupaten Minahasa Utara, Minahasa Selatan dan Minahasa Tenggara pada bulan Februari 2012 - Januari 2013. Penelitian bertujuan untuk mempelajari kelimpahan B. longissima dan musuh alaminya pada pertanaman kelapa. Penelitian dilaksanakan pada tanaman kelapa belum berproduksi dan tanaman kelapa produktif. Pengambilan contoh dilakukan secara acak berlapis atau Stratified random sampling dengan menggunakan sistem kuadran. Hasil penelitian menunjukkan bahwa kelimpahan B. longissima berfluktuasi, kelimpahan tertinggi terjadi pada bulan Agustus dan September 2012 pada tanaman belum berproduksi. Pada tanaman produktif kelimpahan B. longissima tertinggi berturut-turut pada ketinggian tempat 300-600 m dpl terjadi pada bulan Agustus 2012, yaitu 70,30 individu/pelepah, kemudian pada ketingian tempat &gt;600 m dpl terjadi pada bulan September 2012, yaitu 64 individu/pelepah dan pada ketinggian &lt;300 m dpl terjadi pada bulan Juni 2012, yaitu 62 individu/pelepah. Musuh alami B. longissima yang ditemukan pada ketinggian tempat &lt;300 m dpl, 300- 600 m dpl, dan &gt;600 m dpl pada tanaman belum berproduksi adalah parasitoid Tetrastichus brontispae, predator Chelisoches morio, dan entomopatogen Metarhizium anisopliae var. anisopliae. Musuh alami yang ditemukan pada tanaman berproduktif diketiga ketinggian tempat tersebut adalah parasitoid Tetrastichus brontispae, dan predator Chelisoches morio. Entomopatogen M. anisopliae var. anisopliae tidak dijumpai pada tanaman produktif diketiga ketinggian tempat tersebut. Kelimpahan musuh alami dan persentase parasitisme di tiga ketinggian tempat tersebut baik pada tanaman belum berproduksi maupun tanaman produktif ternyata rendah yaitu antara 0,33-14,47%. Hal ini disebabkan pengaruh faktor abiotik dan biotik terhadap kelimpahan B. longissima.</p><p> </p><p> </p>


2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Naseraldeen Baqer Asadalla ◽  
Mohammad Sulaiman Abido ◽  
Asma Abahussain ◽  
Mohamed Shobrak

This research was conducted in four sites at Mahazat as-Sayd reserve in Saudi Arabia to determine the optimum habitats’ constituents for Asian houbara bustard Chlamydotis macqueenii via assessing abiotic and biotic factors with special reference to vegetation aspects. Vegetative parameters were quantified using combinations of distance and line intercept methods. Acquired data were analyzed using cluster analysis and analysis of variance tests. Results indicated that three of the four plant communities of the study sites were dominated by Acacia tortilis with underground cover composed of lesser species. On the other hand, White Jabal was dominated by scrubs composed mainly of Fagonia indica with sparse Acacia trees. Rumrumiyya site recorded the highest species abundance and vegetative coverage (133%) among the sites. It is concluded that Black Jabal and White Jabal sites are used as nesting and foraging habitats for houbaras, whereas Jabal Khurse is specifically a males’ display site. Nevertheless, Rumrumiyya site was used for foraging and shelter. The study confirmed that density and vegetation cover are of prime importance for houbara site selection. However, other factors affecting feeding and behavior of the species must be considered in further studies.


2016 ◽  
Vol 16 ◽  
pp. 14-21 ◽  
Author(s):  
Alexander J McMenamin ◽  
Laura M Brutscher ◽  
William Glenny ◽  
Michelle L Flenniken

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