Influence of potting media compositions on flower production of chrysanthemum (Chrysanthemum morifolium Ramat) cultivar Kikiobiory

Abstract

The experiment was conducted to evaluate the effect of growing media compositions containing cocopeat, FYM and vermiculite in different ratios on potted Chrysanthemum morifolium Ramat cultivar Kikiobiory (standard) for quality flower production. The results revealed that, vegetative growth with maximum plant height, number of leaves, root suckers per plant with delayed flowering were observed in media containing cocopeat?+?FYM (2:1)., whereas, the flower quality parameters like flower diameter and duration of flowering were highest in media containing vermiculite?+?FYM (2:1). However, plants showed the significant vegetative growth with better flowering time and quality in media composition cocopeat?+?vermiculite?+?FYM (1:1:1). Therefore, the findings suggest that for quality flower production of potted Chrysanthemum cv. Kikiobiory, light-weight growing media composition of cocopeat?+?vermiculite?+?FYM (1:1:1) was ideal with better plant morphological development and sustained flowering for display.     

Zinc‐boron interaction effects in oilseed rape

The interaction effect of applied zinc (Zn) and boron (B) on early vegetative growth and uptake of Zn and B by two oilseed rape (canola) (Brassica napus L.) genotypes was investigated in a sand culture experiment under controlled environmental conditions. Two genotypes (Yickadee and Dunkeld) were grown at three Zn levels (0.05, 0.25, and 2.0 mg kg^‐1 soil) and two B levels (0.05 mg kg^‐1 soil and 0.5 mg kg^‐1 soil). Dunkeld produced significantly higher shoot and root dry matter than Yickadee at low Zn and low B supply indicating the superiority of Dunkeld over Yickadee for tolerance to both low Zn and low B supply. Chlorophyll content of fresh leaf tissue was increased significantly by an increase in Zn and B supply. Zinc deficiency enhanced B concentration in younger and older leaves. Boron concentration was higher in older leaves than in the younger leaves irrespective of B deficiency and sufficiency indicating immobility of B in two oilseed rape genotypes tested. Zinc concentration was higher in younger leaves than in the older leaves indicating mobility of Zn. An increased supply of Zn enhanced B uptake under high boron supply only. Zinc uptake in Dunkeld was enhanced significantly with an increased rate of B supply under high Zn supply, while the effect was not significant in Yickadee. Dunkeld proved to be more efficient in Zn and B uptake than Yickadee.     

Identification of alternatives for the management of foliar nematodes in floriculture

The foliar nematodes, Aphelenchoides spp, have emerged as important pests of ornamentals in North America during the last decade. Due to the ban on the use of potentially toxic pesticides, there are currently no nematicides registered to manage foliar nematodes on ornamentals. Therefore, we have evaluated a biological [Burkholderia cepacia (syn Pseudomonas cepacia)], two plant products [clove (Syzygium aromaticum) extract and Nimbecidine (azadirachtin)] and twelve chemical pesticides registered for the management of insects, mites, slugs or diseases of ornamentals, against Aphelenchoides fragariae on the most popular ornamental, hosta (Hosta spp), for two consecutive years. We found ZeroTol (270 g liter-1 peroxyacetic acid), currently labeled as a broad-spectrum fungicide/algicide, to be a very potent nematicide that killed 100% of the nematodes in water suspension. It also caused over 70% reduction in A fragariae population in soil and in the leaves without any phytotoxicity. B cepacia caused 67-85% reduction in A fragariae population in leaves and 50% reduction in the soil whereas insecticidal soap caused over 72% reduction in leaves and 61% reduction in the soil. Clove extract and Nimbecidine did not show any potential for the control of A fragariae on hosta. Although all twelve chemical pesticides were effective in reducing the population of A fragariae in the soil 45 days after treatment (DAT), only diazinon 475 g liter-1 EC, trichlorfon 800 g kg-1 SP, ethoprophos 100 g kg-1 GR, oxamyl 100 g kg-1 GR and ZeroTol caused over 70% reduction in nematode population compared with the control. In the leaves, only diazinon EC, trichlorfon SP, insecticidal soap, oxamyl GR and ZeroTol consistently caused over 70% nematode population reduction compared with the control at 45 DAT in both years. Thus, only diazinon EC, trichlorfon SP, oxamyl GR and ZeroTol consistently caused over 70% reduction in nematode population both in soil and leaves. Due to the recent ban by the US Environmental Protection Agency on the use of the first three of these formulations, only ZeroTol would serve as an effective tool to manage foliar nematodes in ornamentals. Although not as effective as ZeroTol in the soil, insecticidal soap is the only other alternative for foliar nematode management.     

Neonicotinoid insecticides alter diapause behavior and survival of overwintering white grubs (Coleoptera: Scarabaeidae)

The chloronicotinyl, imidacloprid, and the thianicotinyl, thiamethoxam, are effective insecticides against white grubs when applied as preventative treatments during or immediately after egg laying. Their efficacy sharply declines when the grubs reach late-instar stage. As both imidacloprid and thiamethoxam act on post-synaptic nicotinic acetylcholine receptors and modify insect behavior, we hypothesized that the two compounds will interfere with overwintering behavior of scarabs, thus reducing their ecological fitness and exposing them to increased winter mortality. We tested this hypothesis by applying the two compounds curatively against late second-instar and early third-instar Popillia japonica and Cyclocephala borealis grubs in turfgrass. Imidacloprid provided control of P japonica equivalent to the most widely used curative organophosphate, trichlorfon, by 14 days after treatment, but thiamethoxam had no affect. In contrast, both imidacloprid and thiamethoxam caused significant reductions in C borealis populations. Both insecticides altered the overwintering behavior of P japonica by significantly reducing the normal downward movement of grubs in October. Halofenozide, an ecdysone agonist, also caused rapid mortality of the late second-instar C borealis equivalent to trichlorfon, but had no affect on P japonica. In another experiment on a site naturally infested with entomopathogenic nematodes, the exclusive treatment of third-instar P japonica with imidacloprid resulted in no significant mortality in the autumn (up to 15 days after treatment), but caused a significant reduction in the survival of overwintered grubs. There was an increase in the numbers of grubs infected with nematodes in the imidacloprid and trichlorfon treatments compared with control, but these differences were significant only for trichlorfon. These results indicate that imidacloprid can effectively control late second-instars of both P japonca and C borealis and can significantly reduce survival of overwintered third-instar P japonica by altering their normal overwintering behavior.     

Modelling competition of paired columns of Eucalyptus on interplanted grass

Adequate evaluation of competition interfaces of tree growth on intercrops is an important consideration in the assessment of agroforestry systems. Spatial methods wherein positional effect of an observation with respect to trees or columns of trees can be accounted for were examined. Yield ofbhabbar grass (Eulaliopsis binata Ritz) planted under paired and staggered columns of Eucalyptus (Eucalyptus tereticornis Smith) was analysed for four years. Grass production at 7 positions recorded across staggered and paired tree columns was significantly different. Spatial correlations among contiguous observations across paired tree columns were significant. Cyclicity corresponding to seven columns of grass of 3.5 m distance between paired tree columns explained variation in grass production significantly during the first observation year. Additional competition interfaces at 1.75 m and 1.17 m appeared in the subsequent years. These competition interfaces were attributed to pairing of trees and staggering. Error distributions of fitting of cyclic patterns were more acceptable as compared to ANOVA. Possibilities of the use of this methodology in many other agroforestry situations are discussed.