Improving Whitefly Management

Whiteflies (Hemiptera: Aleyrodidae), especially the sweetpotato or cotton whitefly, Bemisia tabaci (Gennadius), are among the most destructive and difficult to manage polyphagous insect pests around the globe [...]

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

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

Incidence of cotton whitefly Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae) infesting cucumber (Cucumis sativus L.) cultivars with reference to cultivar susceptibilities

Field experiments were carried out in Egypt to investigate the infestation rates of cotton whitefly Bemisia tabaci on five cultivars of cucumbers Cucumis sativus during two consecutive late summer seasons from 11 August to 28 October 2015 and 2016. The susceptibilities of the cultivars to infestation by this pest were examined. The five cultivars – Hayl, Nems, Beit Alpha Zena, Bahi and Wafier – were cultivated on a private farm in Mansheyet Saqqara village, Giza. The results showed that whitefly infestation peaks were high in September and October, but low in November in both seasons. The population densities of Bemisia tabaci eggs, nymphs and adults on all the cultivars were slightly higher in 2015 than in 2016. Numbers of B. tabaci eggs, nymphs and adults rose with increasing the temperatures in both seasons, and mean numbers of nymphs and adults also increased with decreasing RH% on all the cultivars. The combination of temperature and humidity was an important regulatory factor affecting B. tabaci development. The results of this study showed that high infestation peaks of B. tabaci occurred in September and October of both seasons. The present results were used to classify the degrees of susceptibility of these cucumber cultivars to B. tabaci infestation as susceptible (S), low resistant (LR) and moderately resistant (MR). It is important that these degrees of susceptibility be referred to the degree of resistance of each cultivar to insect infestation.

Farmers choice of pesticides for the management of whitefly of cotton in Punjab, Pakistan

Cotton, popularly known as white gold, is the king of natural fiber and an important cash crop of Pakistan which earns foreign exchange up to 11.7% and 2.9% of GDP. The present study was carried out in cotton growing areas of four divisions of Punjab to determine the choice of cotton growers for the selection of pesticides for the management of whitefly. The data of hot spots of whitefly were recorded twice a week from April to October during 2015, 2016 and 2017 by using the standard pest scouting method. The study revealed that an increase of 16.09% hot spots of whitefly was detected in 2017 as compared to previous two consecutive years (2015 and 2016). Regarding farmers’ choice for selection of pesticides used to control whitefly, the farmers used Imidacloprid, Acetamiprid, Buprofezin, Clothinadin, Diafenthiuron, Flonicamid, Matrine, Pyriproxifen, Pymetrozine, Spirotetramat. The comparison of three years indicated that maximum farmers preferred to spray Pyriproxifen on the hot spots of cotton whitefly followed by Buprofezin, Acetamiprid and Diafenthiuronwhile Clothinadin and Matrine were used by the minimum numbers of farmers. The use of these insecticides by the farmers during the three years was non-significant. The farmers preferred these pesticides being of third generation, IGRs, Neonicotinoids, environment friendly to human health and safer to natural enemies of whitefly