Combination of generalist predators, Nesidiocoris tenuis and Macrolophus pygmaeus, with a companion plant, Sesamum indicum: What benefit for biological control of Tuta absoluta?

Tuta absoluta is one of the most damaging pests of tomato crops worldwide. Damage due to larvae may cause up to 100% loss of tomato production. Use of natural enemies to control the pest, notably predatory mirids such as Nesidiocoris tenuis and Macrolophus pygmaeus, is increasingly being promoted. However, considering the potential damage caused to tomatoes by these omnivorous predators in the absence of T. absoluta, an alternative solution could be required to reduce tomato damage and improve the predators’ performance. The use of companion plants can be an innovative solution to cope with these issues. The present study aimed to determine the influence of companion plants and alternative preys on the predators’ performance in controlling T. absoluta and protecting tomato plants. We evaluated the effect of predators (alone or combined) and a companion plant (sesame (Sesamum indicum)) on T. absoluta egg predation and crop damage caused by N. tenuis. The influence of an alternative prey (Ephestia kuehniella eggs) on the spatial distribution of predators was also evaluated by caging them in the prey presence or absence, either on tomato or sesame plants or on both. We found that the presence of sesame did not reduce the efficacy of N. tenuis or M. pygmaeus in consuming T. absoluta eggs; hatched egg proportion decreased when N. tenuis, M. pygmaeus, or both predators were present. More specifically, this proportion was more strongly reduced when both predators were combined. Sesame presence also reduced necrotic rings caused by N. tenuis on tomato plants. Nesidiocoris tenuis preferred sesame over tomato plants (except when food was provided only on the tomato plant) and the upper part of the plants, whereas M. pygmaeus preferred tomato to sesame plants (except when food was provided only on the sesame plant) and had no preference for a plant part. Combination of predators N. tenuis and M. pygmaeus allows for better coverage of cultivated plants in terms of occupation of different plant parts and better regulation of T. absoluta populations. Sesamum indicum is a potential companion plant that can be used to significantly reduce N. tenuis damage to tomatoes.

The Use of Halophytic Companion Plant (Portulaca oleracea L.) on Some Growth, Fruit, and Biochemical Parameters of Strawberry Plants under Salt Stress

Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L−1) conditions with or without a halophytic companion plant (Portulaca oleracea L.) were elucidated in a pot experiment. Salt stress negatively affected the growth, physiological (stomatal conductance and electrolyte leakage), and biochemical parameters such as chlorophyll contents (chl-a and chl-b); proline, hydrogen peroxide, malondialdehyde, catalase, and peroxidase enzyme activities; total soluble solids; and lycopene and vitamin C contents, as well as the mineral uptake, of strawberry plants. The companionship of P. oleracea increased fresh weight, dry weight, and fruit average weight, as well as the total fruit yield of strawberry plants along with improvements of physiological and biochemical parameters. This study showed that the cultivation of P. oleracea with strawberry plants under salt stress conditions effectively increased strawberry fruit yield and quality. Therefore, we suggest that approaches towards the use of P. oleracea could be an environmentally friendly method that should be commonly practiced where salinity is of great concern.

Antagonist effects of the leek Allium porrum as a companion plant on aphid host plant colonization

Combining a non-host plant (companion plant or CP) with a target cultivated plant is considered as a promising strategy to reduce pest pressure. Among the companion plants (CP) commonly used in integrated systems, those belonging to the Amaryllidaceae family (chives, garlic, onion, leek) exhibit characteristics related to certain volatile organic compounds (VOCs) with promising repellent potentialities. The aim of this work was to investigate the potential disruption of sweet pepper (host plant) colonization by the green peach aphid (Myzus persicae) when exposed to leek (Allium porrum) as a CP. Retention/dispersion, EPG and clip-cage/Petri dish laboratory experiments were thus performed to study the effect of leek VOCs on aphid settlement/migration, feeding behavior and life history traits parameters, respectively. This work revealed that leek as a CP had a negative effect on aphid feeding behavior, by disturbing the balance between phloem and xylem sap ingestion, but had no influence concerning aphid settlement. Surprisingly, leek as a CP triggered some unexpected probiotic effects on certain life history traits such as aphid survival, biomass, and fecundity, suggesting a possible hormetic effect of leek VOCs on aphid physiology. The possibility of experience-induced preference of aphids for leek VOCs was also discussed.

The Use of Halophytic Companion Plant (Portulaca oleracea L.) on Some Growth, Fruit, and Biochemical Parameters of Strawberry Plants Under Salt Stress

Strawberry is a saline sensitive plant adversely affected under slightly or moderately saline conditions. Growth and biochemical parameters of strawberry plants grown under NaCl (0-, 30-, 60-, and 90 mmol L-1) conditions with or without a halophytic companion plant (Portulaca oleracea L.) were investigated in a pot experiment. Salt stress negatively affected the growth, physiological (stomatal conductance, electrolyte leakage, total soluble solids) and biochemical parameters such as chlorophyll contents (chl-a and chl-b), proline, hydrogen peroxide, malondialdehyde, catalase, and peroxidase enzyme activities, lycopene, vitamin C contents along with the mineral uptake of strawberry plants. The companionship of P. oleacea increased fresh weight, dry weight, and fruit average weight and total fruit yield of strawberry plants along with the improvement of physiological and biochemical parameters. This study showed that cultivating of P. oleracea with strawberry plants under salt stress conditions effectively increased strawberry fruit yield and quality. We, therefore, that approaches towards the use of P. oleracea could be an environmentally friendly method that should be commonly practised where salinity is of great concern.

Effect of Afforestation of Arabica Coffee on the Physical and Sensorial Quality of the Bean

Brazil is a world leader in coffee production, however, the quality of the grain differs between the different production systems, which influences the price paid for the product in the national and international market. Aims: Therefore, the objective of this study was to assess the influence of Arabica coffee afforestation on the physical and sensorial quality of the bean. Methodology: The study was carried out in the Caparaó region, which involves part of the Espírito Santo state region and another part of the Minas Gerais state, Brazil. For the experiment, nine properties with of coffee. Catuaí vermelho IAC-44 was cultivated in two different situations: a plot of land on the full sole and another of wooded land. In each property, two samples were collected, one per area, representing the coffee in full sun and the other the wooded coffee, and in one of the properties samples were collected in two different areas of wooded coffee. Thus, in total, nine samples of crops in full sun and 10 of forest crops with different species were used, such as cedar, eucalyptus, palm heart, polyculture (characterized by shading with species of fruit and wood) and bananas. The samples consisted of seven liters of cherry coffee, selectively harvested, in the middle third of 20 randomly chosen plants. Results: The results showed that the quality of the coffee, physical and sensorial, is influenced by the cultivation system (wooded and in full sun), the degree of influence depends on the type of companion plant. Conclusion: Systems in forest crops with cedar and eucalyptus showed the least number of defects in raw beans and the highest proportion of flat beans (% CG). Treatment of wooded coffee with polyculture showed a higher percentage of coarse mocha (% MG). The cultivation of forested coffee with polyculture has an even better sensory quality, compared to the other treatments studied.

Aphid Behavior on Amaranthus hybridus L. (Amaranthaceae) Associated with Ocimum spp. (Lamiaceae) as Repellent Plants

Various plant species contain biocidal and/or semiochemical components. These can be used for managing insect pests, in order to reduce the use of synthetic pesticides and to improve the quality of vegetable crops. This study was conducted to assess the effect of repellent plants Ocimum gratissimum L. and Ocimum basilicum L. on aphids Aphis craccivora Koch, Aphis fabae Scopoli and Myzus persicae Sulzer when they are associated with Amaranthus hybridus L. plants. The results have shown that in the two approaches tested—Ocimum sp. plants surrounded by A. hybridus plants and the dual-choice test—the number of aphids on the A. hybridus plant associated with either O. gratissimum or O. basilicum was significantly less significant compared to the A. hybridus alone. This first study on the association between A. hybridus and Ocimum spp. shows that the Ocimum species might be used as an alternative method for controlling aphids in order to avoid the use of synthetic pesticides on Amaranthus. The ability of Ocimum spp. to repel pests can make it an important companion plant for farmers, because those plants can not only be used to control pests, but they can also be harvested, providing a direct economic return.

Identifying the repellent genes in Cannabis (C. sativa) through CRISPR screening. The hidden use of Marijuana

Chemical pesticides have caused numerous deaths of people, animals, and plants. As a result, alternative pesticides which are health beneficial and ecological are needed. Cannabis sativa,​ known for its psychoactive effects, can be the solution to this problem. It has excellent repellent characteristics as seen through its use as a companion plant, as well as in-vitro studies. However it has its drawbacks due its controversial nature and lack of research. To solve this problem, our paper aims to locate the non-vital genes in ​C.sativa that cause its repellent effects (R-genes) through CRISPR screening. To optimally identify the R-genes, the random knocked out genes of ​C.sativa were compared to the percentage of alive root-knot nematodes (​M.incognita​) in the plant’s soil. In our experiment, four plants were established per sample: Plant A which is a normal ​Cannabis sativa​, Plant B which is a normal ​Cannabis sativa being infected by ​M.incognita,​ Plant C which is a genetically modified ​Cannabis sativa​, and Plant D which is the same as Plant C except it is being infected by ​M.incognita.​ Then the percentage of alive nematodes will be compared in Plant B and D to identify the R genes. The discovery of R-genes is important as it can be used to discover a new class of repellent molecules. They can also be inserted into crops or household plants, giving them ​Cannabis sativa​’s repellent effects, and benefiting agricultural and health fields.

Evaluation of a Push-Pull System for the Management of Frankliniella Species (Thysanoptera: Thripidae) in Tomato

A push-pull strategy for reducing populations of the thrips Frankliniella occidentalis (Pergande), F. bispinosa (Morgan) and F. tritici (Fitch) in tomato was evaluated. Push components consisted of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component consisted of the companion plant Bidens alba (L.). Replicated field experiments were conducted in 2011 and 2012. Adult and larval thrips were reduced by UV-reflective mulch during early and mid-flowering of tomato. Spray applications of kaolin were effective in reducing adult and larval thrips during early, mid- and late-flowering. The pull effects of the B. alba companion plants were additive and sometimes interactive with the push effects of UV-reflective mulch and kaolin in reducing the adult males of each thrips species and the females of F. bispinosa. The strategy was not effective in reducing the adult females of F. tritici and F. occidentalis. In addition to attracting the Frankliniella species adults, the companion plants were hosts for the thrips predator Orius insidiosus (Say). The companion plants combined with UV-reflective mulch and kaolin proved effective as a push-pull system for suppressing flower thrips, including F. occidentalis which is a serious pest of tomato worldwide.

Sweet Corn, Explored as a Companion Plant, Mitigates Sucking Insects in Industrial Tomato Plants, Pre-flowering Stage

Plant diversification mitigates colonization by herbivorous insects in agricultural systems. Tomato and sweet corn generate raw material, for industrial processing, with outstanding production in Goiás state, Brazil. Yet, little is known about the potential of sweet corn as a companion plant for sucking insects, and natural enemies, in tomato plants. We collected pests and natural enemies in tomato (pre-flowering stage) plants under three treatments: isolated tomato plants (T1), tomato plants with sweet corn in the border (T2), and tomato plants with polyculture (garlic, lettuce, and squash) in the border (T3). The insects were collected by yellow sticky traps. Dalbulus maidis (29.52%), Frankliniella schultzei (23.90%), F. occidentalis (18.72%) and Myzus persicae (15.20%) corresponded to 87.34% of the total insects collected. Tomato plants cultivated with sweet corn on the border had lower infestation of the thrips, F. schultzei as well as the aphid M. persicae. The number of D. maidis and F. occidentalis adults did not change according to the treatments. Diabrotica speciosa and Astylus variegatus were more collected in tomato plants with adjacent sweet corn. Predators and parasitoids represented only 6.62% of the total abundance. Cycloneda sanguinea and parasitoids were more collected in tomato plants with polyculture (T3). Tomato with sweet corn or polyculture favored the abundance of the predator Sphaerophoria scripta. Considerations around the control of insect pests and the sustenance of natural enemies in tomato plants, with sweet corn acting as a companion plant, in the pre-flowering stage of that Solanaceae, are demonstrated.