Diseases and pests of legumes
Most often on peas, less often on beans and broad beans, there is gangrene of the base of the stem and wilting of the legumes, caused by various pathogens (Fusarium solani f. piss, F. oxysporum f. piss, F. oxysporum f. phaseoli, Rhizoctonia solani i inne). One of them causes root neck rot, others clog and damage the vessels in the stems, leading to wilting and death of entire plants. The first symptoms are yellowing of the lower leaves of plants before flowering, or the formation of olive yellow or brown stems on the stems., wet stains.
The most dangerous disease of beans, occurring mainly in wet and cool years, is beans gangrene, called bean anthracnose. On the underside of the leaves and on the surface of the pods appear recessed, roundish, brown spots. When it is more severe, the seeds are also affected, which are one of the sources of infection.
Bean ring bacteriosis is manifested by the appearance of small beans on the leaves and pods (diameter 1-3 mm) brown-green, greasy stains, surrounded by a darker one, reddish border. In the place of these spots, the tissue dries up and dies.
Bean curd rot occurs less frequently than in the previous years in warm and humid years. On the shoots, leaves and pods appear watery, irregular spots, which quickly enlarge and cause rotting of plants.
The disease attacks peas and beans – gangrene blotch, that is, ascochytosis. It hits the leaves, stems, pods and seeds, on which appear roundish, slightly recessed, light brown spots with a dark border. Plants are dying. Similarly, in beans, other pathogens trigger aschytosis, manifested by formation on the stems, leaves and pods of small red-brown spots, which then merge into larger necrotics, rusty or dark brown discoloration. Plants die prematurely.
Peas are also attacked by powdery mildew, which causes, that in the summer on the leaves, the stems, and sometimes the pea pods appear white, mealy raids. Plants dry out earlier, yielding a low yield.
On the beans, rust occurs in beans and peas, caused by pathogens (Uromyces phaseoli, U. fabae, U. piss). The fungi that cause these diseases, initially develop on the spurge, then they are transferred to the above-mentioned plants. In mid-summer, numerous small yellowish spots appear on the leaves and stems, transforming into dusty warts. Plants lose their leaves and wither.
Viral diseases can also occur. The most common is: mosaic of green beans and mosaic of yellow beans. The symptom of the first is dark green spots on the distorted bean leaves, the second - fine, chlorotic stains, limited by the veins of the leaf blade. Plants grow stunted, and the pods are distorted.
In order to prevent the occurrence and control of the above-mentioned diseases, it is necessary to:
– do not grow legumes on the same plot more often than 3-4 years, and in the case of gangrene of peas – more often than not what 5-6 years;
– destroy the spurge and other weeds;
– avoid the vicinity of other legumes, e.g. clover, and also gladioli, which are affected by the same viral diseases;
– use healthy seeds and dress them before sowing with Seed dressing T.;
– carefully clean up all crop residues;
– avoid shaded places, where such diseases spread faster, like for example. gangrenous blotch or fringe bacteriosis;
– in conditions conducive to the occurrence of gangrenous spot (anthracnozy) or ring rot on beans, spray with fungicides after emergence of emergence, then what 10 days; proceed similarly in the case of ascochytosis on broad beans;
– fight aphids.
There are quite a few pests on legumes; the more important ones are listed.
Sprout cream – it is a fly that lays eggs in the ground near germinating bean seeds in May. Hatching white, legless larvae bite into them, often damaging the top of the growth, as a result of which plants stop growing or die. This garbage hibernates in the soil in the pupal stage and occurs in us in two or even three generations. The control consists in treating the seeds with Nexion L in a dose 6 g na 1 kg of seeds.
The bandworm attacks peas, broad bean, sometimes beans. These are small beetles that feed in early spring and gnaw at the edges of the leaves in sinus. They are combated as soon as the first damage is noticed with spraying: gardona 24 EC in concentration 0,3% or Insectophos liquid 50-0,15%.
The pea pod is the most dangerous pest of peas. Beetle in length 4-5 mm is darker with two white spots at the end of the abdomen. The female of this beetle lays eggs on the budding pods. Young larvae enter the pods and bite into the seeds. Hole, which the larva has gnawed, it grows with a thin film and such seeds are difficult to distinguish from healthy seeds. Fighting this pest is very difficult, because the recommended preparations have a 14-day grace period, so they cannot be used after the pods have formed.
The bean pod and the bean pod are equally dangerous pests of beans and broad beans. Each of their seed can feed even a few larvae. In addition, the bean pods are transferred from semen to semen during storage. The control is also difficult when growing on a green pod.
The coneflower pod – the female of this tiny butterfly (wingspan of brown-brown with an olive shade of wings
14-16 mm) lays eggs on pea leaves and flower calyxes. Young greenish caterpillars with a dark head bite into the pods and damage the seeds and contaminate the inside of the pod with droppings and yarn. Pea aphid and beetroot aphid cause the greatest damage in dry years. The other one – matt black with a green or brown tinge – it mainly feeds on broad beans. In addition, aphids transmit viruses that infect the beans. In periods of drought and high temperature, the spider mite also reproduces more intensively (Red spider”), which sucks the juice out of the bean leaves, causing them to turn yellow.
In order to reduce and control these pests it is necessary: apply crop rotation; perform deep digging of beds for winter; carefully destroy plant residues after harvest; sow peas early, that the plants are large and strong at the time of the infestation of mites; dress the seeds; do not delay the harvest of peas and beans; keep the temperature in the rooms low, where we store the seeds of legumes (it is even good to keep them in arbors on the plots).