Cotton leaf trichomes and populations of Empoasca lybica and Bemisia tabaci

The genetic structure of field populations of begomoviruses and their whitefly vector Bemisia tabaci in Pakistan was analyzed. Begomoviruses and B. tabaci populations were sampled from different crops and weeds in different locations in Punjab and Sindh provinces, in areas where cotton leaf curl disease (CLCuD) occurs or does not occur. Phylogenetic analysis based on nucleotide sequences of the intergenic region in the viral DNA-A provided evidence of two clusters of isolates: viruses isolated from species in the family Malvaceae, and viruses isolated from other dicotyledon families. Analysis of the capsid protein (CP) open reading frame grouped isolates into three geographical clusters, corresponding to isolates collected in Punjab, Sindh, or both provinces. Random amplified polymorphic DNA analyses of the B. tabaci population showed that intrapopulation diversity was high at both the local and regional scales. Sequence analysis of the mitocondrial cytochrome oxydase I (mt COI) gene showed that the B. tabaci population was structured into at least three genetic lineages corresponding to the previously described Indian, Southeast Asian, and Mediterranean-African clades. The Indian clade was present only in Punjab, the Mediterranean-African only in Sindh, and the Southeast Asian in both provinces. B. tabaci haplotypes of the Indian clade were found only in the Punjab, where CLCuD occurs. Hence, the geographical distribution of virus and vector genotypes may be correlated, because similar phylogenetic relationships were detected for the viral CP and the vector mt COI genes.

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Cotton leaf curl Gezira virus (African cotton leaf curl Begomovirus).

10.1079/cpc.13816.20210102491 ◽

2021 ◽

Author(s):

Judith K Brown

Keyword(s):

Bemisia Tabaci ◽

Yield Loss ◽

Growing Season ◽

Cotton Leaf ◽

Cotton Production ◽

Natural Spread ◽

Sahel Region ◽

Whitefly Vector ◽

African Sahel ◽

Leaf Curl

Abstract Cotton leaf curl Gezira virus (CLCuGV) is endemic to the African Sahel region (Idris et al., 2000). It is an economically important cotton-infecting begomovirus, and poses a serious threat to cotton production. It causes yield loss in all affected cotton-growing areas in Africa. Losses are difficult to assess, but estimates range up to 20% when infection occurs early in the growing season and/or with highly susceptible cultivars. Natural spread is mainly by the whitefly vector, Bemisia tabaci, which transmits the virus in a persistent, circulative manner. Viruliferous whiteflies on infested/infected plants harbouring CLCuGV imported to other countries are of concern for preventing introduction.

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Some factors affecting numbers of Empoasca lybica (De Berg.) (Homoptera: Cicadellidae) infesting cotton in the Sudan Gezira

Bulletin of Entomological Research ◽

10.1017/s0007485300055358 ◽

1961 ◽

Vol 52 (1) ◽

pp. 191-232 ◽

Cited By ~ 14

Author(s):

R. J. V. Joyce

Keyword(s):

Host Plants ◽

Nitrogen Concentration ◽

Cotton Leaf ◽

Weed Host ◽

Rate Of Increase ◽

Empoasca Lybica ◽

The Relationship ◽

Initial Infestation ◽

Sudan Gezira ◽

River Banks

The Cicadellid, Empoasca lybica de Berg, is an important pest of cotton in the Sudan Gezira, where over 300,000 acres of cotton are grown annually under irrigation. Cotton is sown in mid-August, and the plants are uprooted and burnt the following May. The life-cycle of E. lybica from egg to gravid adult takes 16–24 days, and the adults live for up to 40 days. There is no diapause. During the 100 days from late August to early December when breeding on cotton is of economic importance, a single male and female could give rise to some 50,000 progeny.During May to July, when crops are confined to irrigated gardens and river banks, E. lybica is widely distributed in such places and can be found also on tree hosts, which are numerous especially in the southern Gezira and along river banks. There is circumstantial evidence of displacement over long distances, and the great majority of catches of E. lybica in sticky traps were made before the increase in population on cotton that occurs from September onwards.Of the 53 species of host-plants that have been recorded, only Solanum dubium, Rhynchosia memnonia, Hibiscus spp. and Abutilon spp. are of importance in the ecology of E. lybica. The first two especially are common weeds in fallows, which comprise more than half the land under rotation. Populations of E. lybica in Gezira fallows at the time of cotton germination tended to be greatest where pre-sowing rains (i.e., those falling from 1st July to 15th August) were highest. Correspondingly, initial infestation of cotton was highest in seasons and places receiving the most pre-sowing rains, although density of infestation in any place was affected by sowing date and proximity to irrigated fields and gardens which supported weed host-plants.In order to develop a system of sampling for infestations of E. lybica in the cotton crop, the distribution of nymphs on cotton plants was examined. It was found that nymphs were most numerous in the leafiest zones of the plant and a random choice of leaves seemed an appropriate means of sampling for infestation. The distribution of nymphs within and between cotton fields was also investigated and a standard sampling procedure adopted.Peak infestations on cotton could not be predicted from the level of initial colonisation, or from surveys a month later. Peak infestations were usually inversely related to the level of initial colonisation, especially when comparisons were made between seasons, as at the Gezira Research Farm. That is to say, high levels of initial infestation, which occurred in seasons of good pre-sowing rains, tended to be followed by low rates of increase, and in years of poor pre-sowing rains, initial infestations tended to be low and rates of increase high.The relationship of these findings to those of Cowland & Hanna (1950) and Hanna (1950) are discussed; the hypothesis that pre-sowing mud-splash is a major factor controlling numbers of E. lybica in the Sudan Gezira is discounted, although it is accepted that this factor temporarily reduces populations.The rate of increase of infestations of E. lybica was found to be positively correlated with the concentration of nitrogen recorded 2–4 weeks previously in the cotton leaf. This concentration affected not only the rate of increase of the initial colonisers, but also the rate of recovery of populations during November and December after spray-applications of DDT. The nitrogen concentration in the leaf was increased by nitrogenous fertiliser, with a corresponding increase in infestations of E. lybica. It was also found to be negatively correlated with pre-sowing rains, which, if low, prevent the nitrate in the top 12 in. of Gezira soil being washed to lower levels, but the data presented provide no evidence that the relationship is causal.It is concluded that localities and seasons of poor pre-sowing rains favour a high rate of increase of small populations of E. lybica because of high nitrogen concentration in cotton leaves during September and October. This tendency is augmented by application of nitrogenous fertiliser. A regression equation relating the peak infestations of E. lybica with pre-sowing rainfall and with nitrogenous fertiliser is given and the infestations computed from this are shown not to differ significantly from those recorded in the Gezira as a whole, and in the four main divisions of it separately, during the eight years 1949–1956.

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Genetic identity of the Bemisia tabaci species complex and association with high cotton leaf curl disease (CLCuD) incidence in Pakistan

Pest Management Science ◽

10.1002/ps.2067 ◽

2010 ◽

Vol 67 (3) ◽

pp. 307-317 ◽

Cited By ~ 36

Author(s):

Muhammad Z Ahmed ◽

Paul J De Barro ◽

Jaco M Greeff ◽

Shun-Xiang Ren ◽

Muhammad Naveed ◽

...

Keyword(s):

Bemisia Tabaci ◽

Species Complex ◽

Genetic Identity ◽

Cotton Leaf ◽

Cotton Leaf Curl Disease ◽

Leaf Curl Disease ◽

Leaf Curl

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PENGARUH KERAPATAN BULU DAUN PADA TANAMAN KAPAS TERHADAP KOLONISASI Bemisia tabaci GENNADIUS

Jurnal Penelitian Tanaman Industri ◽

10.21082/jlittri.v11n3.2005.101-106 ◽

2020 ◽

Vol 11 (3) ◽

pp. 101

Author(s):

I G.A.A. INDRAYANI ◽

EMY SULISTYOWATI

Keyword(s):

Gossypium Hirsutum ◽

Bemisia Tabaci ◽

Insect Pest ◽

Morphological Characteristics ◽

Resistant Variety ◽

Cotton Leaf ◽

Trichome Density ◽

Randomized Design ◽

Cotton Whitefly

ABSTRACT Ketahanan tanaman terhadap serangga hama berdasarkan karakter morfologi bulu (trichom) pada daun merupakan salah satu cara potensial mengurangi penggunaan insektisida kimia dalam pengendalian hama. Serangga hama pengisap Bemisia tabaci pada tanaman kapas juga dapat dikendalikan dengan menggunakan varietas kapas resisten berdasarkan karakter morfologi bulu daun. Penelitian peranan kerapatan bulu daun pada tanaman kapas terhadap kolonisasi B. tabaci Gennadius dilakukan di Kebun Percobaan Pasirian, Kabupaten Lumajang, dan di Laboratorium Entomologi Balai Penelitian Tanaman Tembakau dan Serat Malang, mulai April hingga Juli 2005. Tujuan penelitian adalah untuk mengetahui peranan kerapatan bulu daun pada beberapa aksesi plasma nutfah kapas terhadap kolonisasi B. tabaci. Perlakuan terdiri atas 11 aksesi plasma nutfah kapas yang dipilih berdasarkan penilaian visual pada karakter kerapatan bulu daun yang mewakili kerapatan bulu rendah hingga tinggi, yaitu: (1) KK-3 (KI 638), (2) Kanesia 1 (KI 436), (3) A/35 Reba P 279 (KI 257), (4) Acala 1517 (KI 174), (5) Asembagus 5/A/1 (KI 162), (6) 619- 998xLGS-10-77-3-1 (KI 76), (7) DP Acala 90 (KI 23), (8) TAMCOT SP 21 (KI 6)), (9) Kanesia 8 (KI 677), (10) CTX-8 (KI 494), dan (11) CTX-1 (KI 487). Penelitian disusun dalam rancangan acak lengkap (RAL) dengan 10 ulangan. Paramater yang diamati adalah jumlah bulu daun, telur dan nimfa pada 1 cm2 luas daun, serta jumlah imago B. tabaci pada daun ketiga dari atas tanaman. Hasil penelitian menunjukkan bahwa kerapatan bulu daun berkorelasi positif dengan kolonisasi B. tabaci (R=0,9701). Semakin tinggi kerapatan bulu daun, semakin meningkat kolonisasi B. tabaci. Kolonisasi B. tabaci lebih tinggi pada CTX-1, CTX-8, Kanesia 8, dan KK-3 (150-250 individu/cm 2 luas daun) karena tingkat kerapatan bulu daun juga lebih tinggi (150-300 helai/cm 2 luas daun) dibanding TAMCOT SP 21, DP Acala 90, 619-998xLGS-10-77-3-1, Asembagus 5/A/1, Acala 1517, A/35 Reba P 279, dan Kanesia 1 yang memiliki kerapatan bulu daun (0-100 helai/cm 2 luas daun) dan tingkat kolonisasi B. tabaci (<100 individu/cm 2 luas daun) lebih rendah. Kata kunci : Kapas, Gossypium hirsutum, plasma nutfah, hama, Bemisia tabaci, trichom, kolonisasi, Jawa Timur ABSTRACT Role of trichome density of cotton leaf to colonization of Bemisia tabaci Gennadius Trichome-based host plant resistance offers the potential to reduce chemical insecticides used in insect pest control. Cotton whitefly, Bemisia tabaci can be controlled by using resistant variety based on trichome density as plant morphological characteristics. The study on the role of trichome density of cotton accessions on the colonization of B. tabaci was carried out at Pasirian Experimental Station at Lumajang, and at Entomology Laboratory of Indonesian Tobacco and Fiber Crops Research Institute (IToFCRI ) in Malang from April to July 2005. Treatments included 11 cotton accessions, viz. (1) KK-3 (KI 638), (2) Kanesia 1 (KI 436), (3) A/35 Reba P 279 (KI 257), (4) Acala 1517 (KI 174), (5) Asembagus 5/A/1 (KI 162), (6) 619-998xLGS-10-77-3-1 (KI 76), (7) DP Acala 90 (KI 23), (8) TAMCOT SP 21 (KI 6)), (9) Kanesia 8 (KI 677), (10) CTX-8 (KI 494), and (11) CTX-1 (KI 487). The experiment was arranged in completely randomized design with ten replications. Parameters observed were trichome density, number of eggs and nymphs on one cm2 of leaf and adult of B. tabaci on 3rd highest leaf of cotton plant. The result showed that trichome density was positively correlated with B. tabaci colonization (R=0,9701) in which higher trichome density of cotton leaf has resulted in great colonization of B. tabaci. Bemisia tabaci colonisation was higher on CTX-1, CTX-8, Kanesia 8, and KK-3 (150-250 individu/cm2 of leaf) due to dense trichome (150-300 trichomes/cm2 leaf) as compared with other accessions, viz. TAMCOT SP 21, DP Acala 90, 619-998xLGS-10-77-3-1, Asembagus 5/A/1, Acala 1517, A/35 Reba P 279, and Kanesia 1 which showed less density of leaf trichome (0-100 trichomes/cm2 of leaf) and B. tabaci colonization (< 100 individu/cm2 of leaf). Key words : Cotton, Gossypium hirsutum, cotton accession, pest, Bemisia tabaci, trichome, colonization

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Demographic Expansion of the Predominant Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Mitotypes Associated With the Cotton Leaf Curl Virus Epidemic in Pakistan

Annals of the Entomological Society of America ◽

10.1093/aesa/saz002 ◽

2019 ◽

Vol 112 (3) ◽

pp. 265-280 ◽

Cited By ~ 8

Author(s):

Jorge R Paredes-Montero ◽

Usman Hameed ◽

Muhammad Zia-Ur-Rehman ◽

Ghulam Rasool ◽

Muhammad Saleem Haider ◽

...

Keyword(s):

Bemisia Tabaci ◽

Cotton Leaf ◽

Demographic Expansion ◽

Cotton Leaf Curl Virus ◽

Leaf Curl Virus ◽

Leaf Curl

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CAPACIDADE PREDATÓRIA DE Chrysoperla externa SOBRE Bemisia tabaci biótipo B EXPOSTAS AO FUNGO Metarhizium anisopliae

Scientia Agraria ◽

10.5380/rsa.v12i2.33823 ◽

2011 ◽

Vol 12 (2) ◽

Author(s):

Eunice Cláudia SCHLICK-SOUZA ◽

Luciana Cláudia TOSCANO ◽

Wilson Itamar MARUYAMA ◽

Genivaldo David SOUZA-SCHLICK ◽

Elisa ADRIANO ◽

...

Keyword(s):

Functional Response ◽

Bemisia Tabaci ◽

Metarhizium Anisopliae ◽

Active Principle ◽

Cotton Leaf ◽

Type I ◽

The Difference ◽

Predatory Capacity ◽

B Biotype ◽

Leaf Disks

O objetivo desta pesquisa foi determinar a influência de Metarhizium anisopliae (Metsch) sobre a capacidade predatória e a resposta funcional de Chrysoperla externa (Hagen) alimentada com Bemisia tabaci biótipo B advindas de algodoeiro. Larvas do predador foram alimentadas após a eclosão com ovos de Anagasta küeniella até o 3º ínstar, posteriormente alimentadas com ninfas de mosca-branca, em densidade superior à capacidade de consumo (150 ninfas/indivíduo). As ninfas foram oferecidas sobre discos de folhas de algodoeiro (5 cm diâmetro), 24 h após a aplicação com: T1: Testemunha (água); T2: M. anisopliae na concentração de 105 conídios cm-3; T3: 108 conídios cm-3 oriundo de Metharril® com formulação de 1,0 x 109 conídios cm-3 viáveis do princípio ativo M. anisopliae. A capacidade predatória foi obtida pela diferença entre o número de ninfas fornecidas e as remanescentes e a resposta funcional foi avaliada a partir de cinco diferentes densidades de ninfas (130, 160, 190, 220 e 250), contando-se o número de ninfas predadas após 24, 48, 72 e 96 horas. O fungo entomopatogênico M. anisopliae não influenciou a capacidade predatória de C. externa que variou de 70,6 indivíduos na maior concentração e 87,1 na testemunha. A resposta funcional do predador foi do tipo II, após 24 horas e do tipo I para 48, 72 e 96 horas. A capacidade predatória de C. externa não foi afetada pelo fungo M. anisopliae nas concentrações utilizadas. A resposta funcional para 24 h evidenciou tipo II e para os demais tempos tipo I independente das concentrações de fungo utilizadas. ABSTRACT The objective of this study was to determine the influence of Metarhizium anisopliae on the predatory capacity and functional response of Chrysoperla externa fed Bemisia tabaci B biotype rearing cotton. The stock rearings of B. tabaci B biotype and C. externa were maintained in cages according to preexisting methodologies. Upon hatching, predator larvae were fed on eggs of Ephestia küehniella until their 3rd instar and then fed on whitefly nymphs in density exceeding their intake capacity (150 nymphs/individual). The nymphs were offered on cotton leaf disks (5 cm diameter), 24 hours after the treatments application following: T1: Control (water); T2: M. anisopliae at the concentration of 105 conidia cm-3; T3: 108 conidia cm-3 origined from Metharril® formulation of the 109 viable conidia cm-3 M. anisopliae active principle. The predatory capacity was obtained by the difference between the numbers of nymphs supplied and nymphs left. Five different nymphal densities (130, 160, 190, 220, and 250) were selected for the functional response study. The number of nymphs preyed was recorded after 24, 48, 72, and 96 hours. The M. anisopliae entomopathogenic fungi did not influence predatory capacity of C. externa which ranged from 70.6 individuals at the highest concentration to 87.1 in the control. Conclued that the C. externa predatory capacity was not affected by fungi M. anisopliae concentrations. The predator showed a type-II functional response after 24 hours, and a type-I response after 48, 72, and 96 hours independent from fungi concentrations.

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