Efficacy of Eco-friendly Insecticides Against Rice Leaf Folder under kharif Rice-Crop-Ecosystem of Manipur valley

AbstractExtreme high-temperature events are the key factor to determine population dynamics of the rice leaf folder,Cnaphalocrocis medinalis(Guenée), in summer. Although we know that adult of this insect can migrate to avoid heat stress, the behavioral response of larva to high temperature is still unclear. Therefore, impacts of high temperature on behavioral traits ofC. medinalisincluding host choice, settling and folding leaf were observed. The results revealed that these behavioral traits were clearly influenced by high temperature. The larvae preferred maize leaves rather than rice and wheat at normal temperature of 27°C, but larvae experienced a higher temperature of 37 or 40°C for 4 h preferred rice leaves rather than maize and wheat. Capacity of young larvae to find host leaves or settle on the upper surface of leaves significantly reduced when they were treated by high temperature. High temperature of 40°C reduced the leaf-folding capacity of the third instar larvae, but no effects were observed on the fourth and fifth instar larvae. Short-term heat acclimation could not improve the capacity of the third instar larvae to make leaf fold under 40°C.

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Komposisi dan Sebaran Patotipe Xanthomonas oryzae pv. oryzae, Penyakit pada Padi di Nusa Tenggara Barat

Jurnal Penelitian Pertanian Tanaman Pangan ◽

10.21082/jpptp.v34n2.2015.p113-120 ◽

2015 ◽

Vol 34 (2) ◽

pp. 113

Author(s):

Sudir Sudir ◽

Dini Yuliani ◽

Lalu Wirajaswadi

Keyword(s):

Disease Severity ◽

Xanthomonas Oryzae ◽

Rice Crop ◽

Bacterial Leaf Blight ◽

Rice Varieties ◽

Rice Leaf ◽

Rice Leaves ◽

Differential Varieties ◽

Planting Season ◽

Screen House

<p>A study was carried out to identify the composition and distribution of Xanthomonas oryzae pv. oryzae (Xoo) pathotypes on rice crop in West Nusa Tenggara, during the 2012 planting season. Three activities were conducted, namely collection of rice leaf samples from the fields, isolation of Xoo from the leaf samples at the laboratory, and testing pathotypes of Xoo at the screen house. Rice leaves showing typical bacterial leaf blight (BLB) symptom were collected from various farmers’ fields. The samples were detached and put into paper envelopes, and were taken to the laboratory for isolation of Xoo, at the Laboratory of Pythopathology of Indonesian Center for Rice Research (ICRR), Sukamandi. Pathotype testing was done in the ICRR screen house by inoculating the leaves of five differential rice varieties using inocula of the Xoo isolates. Resistance of the rice differential varieties was determined based on the BLB disease severity. Inoculated plant with disease severity ≤11% was considered resistant (R) and disease severity >11% was susceptible (S). From the 240 samples of rice leaf infected with BLB collected from West Nusa Tenggara, 232 Xoo isolates were obtained. The Xoo pathotype identification showed that pathotype IV was the most dominant in West Nusa Tenggara during the 2012 planting season, numbering 118 isolates or 51.0% out of the total isolates, followed by pathotype VIII (67 isolates or 29.0%), and pathotype III (47 isolates or 20.0%).</p>

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