The cotton aphid, Aphis gossypii is an economically significant insect pest infesting various important crops and vegetables. The neonicotinoid, acetamiprid was recommended against aphids with excellent results. Resistance emergence and environmental pollution makes acetamiprid a favorable alternative to conventional insecticides. The aims of the present work were to predict acetamiprid resistance risk in A. gossypii, investigate cross resistance to other tested insecticides and explore acetamiprid stability in the absence of selection. A field-collected population from Sharqia governorate, Egypt was selected with acetamiprid. After 16 generations of selection, there was a 22.55-fold increase in LC50 and the realized heritability (h2) of resistance was 0.17. Projected rates of resistance indicated that, if h2 = 0.17 and 50% of the population was killed at each generation, then a tenfold increase in LC50 would be expected in 12.2 generations. If h2 was 0.27 then 7.63 generations would be needed to achieve the same level. In contrast, with h2 of 0.07 it necessitates about 30 generations of selection to reach the same level. Cross resistance studies exhibited that the selected strain showed obvious cross resistance to the other tested neonicotinoid members, moderate cross resistance to alpha-cypermethrin and no cross resistance to pymetrozine. Fortunately, resistance to acetamiprid in the cotton aphid was unstable and resistance reverses the nearby susceptible strain throughout five generations without exposure to acetamiprid. Our results exhibited cotton aphid potential to develop resistance to acetamiprid under continuous selection pressure. The instability of acetamiprid makes A. gossypii amenable to resistance management tactics such as rotation with pymetrozine.

The “second generation” of glyphosate-tolerant soybean (GT2 soybean) was developed through a different technique of insertion of the glyphosate-insensitive EPSPs gene, in comparison with “first generation” of glyphosate-tolerant soybean. However, there is not enough information available about glyphosate selectivity in GT2 soybean and the effects on the quality of seeds produced. The aim of this study was to evaluate tolerance to glyphosate and seed quality of soybean cultivar NS 6700 IPRO (GT2) with cp4-EPSPs and cry1Ac genes, after application at post-emergence (V4). The experiment was conducted in a randomized block design with four replicates and seven treatments, or rates of glyphosate (0; 720; 1,440; 2,160; 2,880; 3,600; 4,320 g of acid equivalent − a.e. · ha−1). Assessments were performed for crop injury, SPAD index and variables related to agronomic performance and seed quality. A complementary trial with the same cultivar and treatments in a greenhouse was conducted in a completely randomized design with four replications. Data analysis indicated no significant effect of glyphosate on V4 on agronomic performance and physiological quality of seeds, for two growing seasons. The soybean cultivar NS 6700 IPRO (GT2), with cp4-EPSPs and cry1Ac genes, was tolerant to glyphosate up to the maximum rate applied (4,320 g a.e. · ha−1) at post-emergence (V4). The quality of soybean seeds was not affected by glyphosate up to the maximum rate applied (4,320 g a.e. · ha−1) at post-emergence (V4).

Silicon (Si) is the second most abundant element present in the lithosphere, and it constitutes one of the major inorganic nutrient elements of many plants. Although Si is a nonessential nutrient element, its beneficial role in stimulating the growth and development of many plant species has been generally recognized. Silicon is known to effectively reduce disease severity in many plant pathosystems. The key mechanisms of Si-mediated increased plant disease resistance involve improving mechanical properties of cell walls, activating multiple signaling pathways leading to the expression of defense responsive genes and producing antimicrobial compounds. This article highlights the importance and applicability of Si fertilizers in integrated disease management for crops.

Barley scald, caused by Rhynchosporium commune is one of the most prevalent diseases in barley (Hordeum vulgare L.) worldwide. The primary loss from scald is reduced yield, which can exceed 25% in dry areas. In our earlier studies, we developed a low-resolution linkage map for recombinant inbred lines of the cross Tadmor/WI2291. Quantitative trait loci (QTLs) for scald were localized on chromosomes 2H and 3H flanked by Simple Sequence Repeat (SSR) markers HVM54 and Bmac0093b on 2H and HVLTPP8, HVM62 and Bmag0006 on 3H. These chromosome 3H markers were found to be located close to the Rrs1 − R. commune resistance gene(s) on chromosome 3H. In this study, 10 homozygous resistant and 10 homozygous susceptible plants each from the F7 population of Tadmor/ Sel160, a panel of 23 barley varieties used routinely in the International Centre for Agricultural Research in the Dry Areas (ICARDA) breeding program and three populations were used for scald resistance screening using 25 DNA markers that are located very close to scald resistance gene(s) on barley chromosomes. Only five of those markers clearly discriminated co-dominantly between resistant and susceptible plants. These markers, Ebmac0871- SSR, HVS3-SCAR, Bmag0006-SSR, reside on different arms of barley chromosome 3H. Ebmac871 is localized on the short arm of 3H and HVS3 and Bmag0006 are localized on the long arm of 3H. This result indicates that the scald resistance genes which they tag are probably close to the centromeric region of this chromosome. Scald resistance from several sources map to the proximal region of the long arm of chromosome 3H, forming the complex Rrs1 locus. The availability of highly polymorphic markers for the discrimination of breeding material would be extremely useful for barley breeders to select for the trait at the DNA level rather than relying on phenotypic expression and infection reaction.

Bollworms comprise the most harmful and economically relevant species of lepidopteran. Helicoverpa gelotopoeon (D.) (Lepidoptera: Noctuidae) is native to America and affects many crops. Tobacco is an industrial crop in which methods of pest control rely mainly on the application of insecticides. To develop new eco-friendly strategies against insect pests it is very important to overcome the side effects of insecticides. The utilization of fungal entomopathogens as endophytes is a new perspective that may accomplish good results. The present study aimed to evaluate the ability of endophytic Beauveria bassiana (Bals.-Criv.) Vuill. to affect H. gelotopoeon life parameters and feeding behavior on tobacco plants. Beauveria bassiana LPSC 1215 as an endophyte did not reduce the amount of vegetal material consumed by H. gelotopoeon larvae but affected the life cycle period of the plague, particularly the larval and adult stages. Also, egg fertility was affected since adults laid eggs that were not able to hatch. The results of this investigation provide new information on endophytic entomopathogen potential to be incorporated in Integrated Pest Management (IPM) programs.