FHB of wheat is a serious regional problem in Punjab. An outstanding bread wheat line RP-1/10 and three durum lines viz; WH 896, HD 4715 and MPO 1192-resistant to FHB have been identified. Aphids are important insect-pests in wheat and the FHB severity can be significantly reduced by more than 30%, by controlling these aphids by the application of Monocrotophos (insecticide) at boot + heading or at heading alone. A single application of Monocrotophos @ 0.1% followed 72h later by Tilt@0.1% at heading significantly improved FHB control and grain yield. The strobilurin fungicide-Amistar@ 0.1%, applied as a single spray at heading, was the best treatment in reducing FHB severity and improving grain yield. The efficacy of the fungicide was much higher in bread wheat compared to durum wheat. The results suggest that wheat aphids are important in FHB development and their management through insecticide in combination with fungicide can reduce FHB and improve grain yield.
Aphids have acquired the status of major pest in North-western plains of India. A complex of five species infests the wheat in this part of the country. The diatomaceous earth (DE) has the potential to substitute the most widely used method of chemical control. Laboratory and field investigations were conducted to evaluate the effectiveness of DE either as soil or foliar application for suppression of wheat aphids during 2013–2014 and 2014–2015. The fecundity, adult longevity and total developmental duration of Rhopalosiphum padi decreased with the increasing dosage of soil application of DE in laboratory evaluation. However in field studies, no significant difference in aphid population was observed among different levels of DE application in soil. Foliar application of DE 150 kg/ha and higher dosages significantly reduced aphid population for initial two days but thereafter it had no effect on aphid prevalence. Wheat plant dusted with different dosages of DE did not show any visible injury but the reduction in chlorophyll content was observed in them. Overall, poor field efficacy coupled with loss of chlorophyll and safety issues relating to foliar application of DE proved against its use for control of sucking insect pests.
Authors:X.L. Liu, B.Y. Lu, C.Y. Wang, Y.J. Wang, H. Zhang, Z.R. Tian, and W.Q. Ji
The aphid Sitobion avenae F. is one of the most harmful pests of wheat growth in the world. A primary field screening test was carried out to evaluate the S. avenae resistance of 527 wheat landraces from Shaanxi. The results indicated that 25 accessions (4.74%) were resistant to S. avenae in the three consecutive seasons, of which accession S849 was highly resistant, and seven accessions were moderately resistant. The majority of S. avenae resistant accessions come from Qinling Mountains. Then, the genetic variability of a set of 33 accessions (25 S. avenae resistant and 8 S. avenae susceptible) originating from Qinling Mountains have been assessed by 20 morphological traits and 99 simple sequence repeat markers (SSRs). Morphological traits and SSRs displayed a high level of genetic diversity within 33 accessions. The clustering of the accessions based on morphological traits and SSR markers showed significant discrepancy according to the geographical distribution, resistance to S. avenae and species of accessions. The highly and moderately resistant landrace accessions were collected from the middle and the east part of Qinling Mountains with similar morphology characters, for example slender leaves with wax, lower leaf area, and high ear density. These S. avenae resistant landraces can be used in wheat aphid resistance breeding as valuable resources.